BUG: LooseVersion was used incorrectly
closes #8581 

Version comparison had a formatting error resulting in "TypeError: expected string or buffer" and preventing Spyder from loading (and probably other issues). Fixed.

can you add a note in v0.15.1 (refing the issue). In what cases would this fail? (e.g. if you have no deps then it bypasses that whole try,except), but when would it hit that error?
 Not sure if you mean just leave a comment here? -- I found the issue when the offending code prevented Spyder from launching after I installed the Google Python API. It was also causing the pandas library to think that the API could not be imported, or an error when one wrote "from  pandas.io import gbq"
 this is not very well tested (really hard as we don't have an authentication setup). Just trying to see if only having _some_ deps caused this to fail.
 merged via https://github.com/pydata/pandas/commit/403f38da35ab04d3997f61db3c98134fe02910d3
thanks!
 I'll see about rerunning the integration tests this coming weekend.
 I'm having some permissions issues with our Bigquery automated test suite. However, as with https://github.com/pydata/pandas/pull/8590 it seems that gbq's test_requirements() method is failing if the user has `bigquery` installed (which is a requirement for the automated tests of gbq). 

```
__main__.test_requirements ... SKIP: pandas requires google-api-python-client >= 1.2.0 for Google BigQuery support, current version 1.2
```

Of course, this may be unrelated to this patch - just thought I'd mention it. It looks like this can be resolved by simply correcting the test_imports() method:

```
           if LooseVersion(_GOOGLE_API_CLIENT_VERSION) >= '1.2':
                _GOOGLE_API_CLIENT_VALID_VERSION = True
```

I'm not sure what the consequences of doing this are though...
