handle the stop command

handle the stop command

Handle the stop command. The stop command waits for the peer to
disconnect, that means the peer has exited, so it is safe to
return to the user control. By this way, we ensure a stop command
followed by a start or a destroy won't fail with a race condition
because the start command is not yet finised.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: Michel Normand <normand@fr.ibm.com>