Fix possible shell injection in linux.service action.
Fix possible shell injection in linux.service action.

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