retain behaviour that st2common.utils.shell.run_command returns stdout and stderror as strings in Py3/2
retain behaviour that st2common.utils.shell.run_command returns stdout and stderror as strings in Py3/2

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