Add tests for st2 --version CLI command.
Add tests for st2 --version CLI command.

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