Revert "Try using older version of pip."
Revert "Try using older version of pip."

This reverts commit 2b5e3e931829c5ce7c287b4824367e6073592476.

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