TST: Fix missing import in io/tests/test_json
Nose import is missing. If you get to the error at the last line, it throws an error because nose is never imported.

were line endings screwed up?
 no, I mean that it raises `nose.skipTest` but never has `import nose`. Just ran the test and it failed that way, which is how I noticed it.
 however, it looks like github screwed up the commit
 so I'll redo it on my computer :-/
 hmm I ran these using nosetests directly so maybe that's why didn't have a problem 
 You have to get a urllib2.UrlError to see it...
 Much better now...as you can see, it's a oneline change.
 yesterday: https://dev.twitter.com/blog/api-v1-is-retired lol
