engine: Declare a multiple runner for PersistentSetupNetworks

Executing a multiple PersistentSetupNetworks should be
invoked in a separate thread per command, therefore
a dedicated multiple action runner is set for the
PersistentSetupNetworks.

Change-Id: I92b4c7a31adbe2d7384a8857d2deba2ad0809d63
Signed-off-by: Moti Asayag <masayag@redhat.com>