Ignore fetch info if it starts with POST

I haven't gotten the tests to pass, I get:
```
  File "/home/medwards/forks/GitPython/git/test/lib/asserts.py", line 16, in <module>
    'assert_mode_755'] + tools.__all__
AttributeError: 'module' object has no attribute '__all__'
```
Where tools is from `from nose import tools`

So that's great.

I also haven't manually tested this but based on output I copied and pasted into #94 it should at least fix my part of the problem.