core: Rename can-do-action message name and description

Can-do-action message renamed to reflect what it really validates:
NETWORK_IN_USE was changed to ACTION_TYPE_FAILED_NETWORK_NAME_IN_USE
and so its description.

Change-Id: I5369db06e262f0f2afd9ab2f8d5dc88e20659946
Signed-off-by: Moti Asayag <masayag@redhat.com>