Fix fixate-requirements.py so it works with pip 10.0.
Fix fixate-requirements.py so it works with pip 10.0.

StackStorm/st2,StackStorm/st2,Plexxi/st2,nzlosh/st2,StackStorm/st2,Plexxi/st2,Plexxi/st2,nzlosh/st2,StackStorm/st2,nzlosh/st2,Plexxi/st2,nzlosh/st2