Fix psutil usage on el6 for job cancel
Fix psutil usage on el6 for job cancel

psutil will fail to import on el6 due to not being able to access a
pseudo terminal.  This issues a SIGKILL to the proot process in order to
force the stop

snahelou/awx,wwitzel3/awx,wwitzel3/awx,snahelou/awx,wwitzel3/awx,snahelou/awx,snahelou/awx,wwitzel3/awx