Only apply workaround for permissions issue to /home/travis when running on Xenial.
Only apply workaround for permissions issue to /home/travis when
running on Xenial.

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