engine: Change DetachNetworkToVdsGroup to non-transactive

The command will be used also for removing the network
from the hostis. For that purpose the command should
be managed as a non-transactive.

Change-Id: I419ddbd3b657dae7829f15d45399b3b1a4996172
Signed-off-by: Moti Asayag <masayag@redhat.com>