BUG: The 'jobComplete' key may be present but False in the BigQuery query results
xref #9141 

Fixes an issue when looking for 'totalRows' on a large dataset that is not finished in between two subsequent checks.

cc @jacobschaer

ok?

@aaront pls add a release note in v0.15.1 for this
 @jreback Hope I did this right. Let me know if there's an issue (it's my first pull request)
 yep that looks good

since this is not tested by pandad directly id like Jacob to concur on this
 I'm surprised this change is needed - the line of code you changed came directly from Google's example. However, I always thought it was silly the way they did it... So, I guess what you encountered is that there exist cases where the job is not yet finished and either 'jobComplete' is absent, _or_ it is False? If it is exclusively the latter, there might be a better way to write this...

I haven't had a chance to run the regression suite.

Thanks for the pull request though @aaront 
 I ran a little test for this by adding a bit of code to to the existing 0.15 code:

``` python
while(not 'jobComplete' in query_reply):
    print('Job not yet complete...')
    query_reply = job_collection.getQueryResults(
                    projectId=job_reference['projectId'],
                    jobId=job_reference['jobId']).execute()
if (not 'totalRows' in query_reply):
    print(query_reply)
total_rows = int(query_reply['totalRows'])
```

And received the following output:

```
Job not yet complete...
{u'kind': u'bigquery#getQueryResultsResponse', u'etag': u'"1R8EtuJeC1ZTqaGooyltyIvODk8/W9GOBbLTm4BKUyjNgBAQorULao0"', u'jobComplete': False}
```

Here's the error stacktrace:

``` python
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
<ipython-input-3-078620e7215f> in <module>()
      1 query = geotab.BigQueryBuilder('PerformanceTime', FROM_DATE, TO_DATE).build()
----> 2 df = pd.read_gbq(query, project_id='XXXXXX')

C:\Miniconda\envs\mygeotabenv\lib\site-packages\pandas\io\gbq.py in read_gbq(query, project_id, index_col, col_order, reauth)
    369 
    370     connector = GbqConnector(project_id, reauth = reauth)
--> 371     schema, pages = connector.run_query(query)
    372     dataframe_list = []
    373     while len(pages) > 0:

C:\Miniconda\envs\mygeotabenv\lib\site-packages\pandas\io\gbq.py in run_query(self, query)
    193         if (not 'totalRows' in query_reply):
    194                 print(query_reply)
--> 195         total_rows = int(query_reply['totalRows'])
    196         result_pages = list()
    197         seen_page_tokens = list()

KeyError: 'totalRows'
```
 Thanks - that's a bit frustrating they would change that. I'm still trying to get my bq credentials fixed so I can re-run the integration suite and say for sure.
 Any updates on this?
 @jacobschaer progress on this?
 @jacobschaer update on this?
 The status is that Google managed to break something in their API and now our regression suite won't pass. This doesn't have anything to do with this commit, so we were trying to decide what to do. Frankly, the test that is now failing may have been a bit excessive and we can probably get away with reducing/removing it.
 Update - the issue with the regression suite seems to have resolved itself (by magic?). I ran the test suite against a modified version of this code (fixed the '1.2.0' != '1.2' in the _test_imports method by hand). Everything looks good.

Technically this is duplicated by https://github.com/pydata/pandas/issues/9141. @jreback - how do you wish to proceed?

@sean-schaefer - was there an addition you wanted to make to this PR to fix the '1.2.0' issue or anything else? I thought we had talked about you modifying this code. Or should we just do a seperate pull request?
 @jacobschaer I already sneaked the LooseVersion check in #8590 but that PR hasn't been accepted. @jreback Is there something more on our end needed to get that done?

I remember we discussed another modification here, but cannot recall the specifics. If either of us happen to remember, we can open a different PR for it.
 can you rebase and move the release note to 0.16.0?
 @jreback done and done
 @aaront ok thanks. 

@jacobschaer how is testing proceeding? ok with this change?
 @jreback - Testing looks good. Now to see if we can get https://github.com/pydata/pandas/pull/8590 in as well. I'm going to try it now.
 @jacobschaer this mergable?
 The original hope was that https://github.com/pydata/pandas/pull/8590 would make it in first, since it technically is required for the integration suite to "pass". Unfortuantely, there seems to be an issue with Travis that neither @sean-schaefer nor I can track down. Who would the be go-to person for that?
 @jacobschaer ok, we can 'skip' the tests for now if you can assure that:

1) this passes locally for you guys
2) this is a rationale / correct change
 @jreback I've been using this change daily for a few months and can confirm it makes pd.read_gbq() functional.

@jacobschaer I'm not sure #8590 is still actually an issue. As I mentioned before, I use this daily and if the notebook process is launched from a directory that doesn't contain a credential file, running pd.read_gbq() will invoke an auth flow just fine. I can confirm this works in Safari and Chrome on the Mac, and Chrome on Windows. This is with python-gflags 2.0 and google-api-python-client 1.3.1 installed.
 merged via https://github.com/pydata/pandas/commit/3039533b303823b671fdc71908247cfee5d79545

thanks!
