core: Add audit log when removing networks from iSCSI bond.

Adding an audit log to indicate the user that the removed networks
from the iSCSI bond, will only take affect, after the Hosts will be moved
to maintenance and activated again.

Change-Id: I087818bb48cc9243e76b2cb850e6262104537f3c
Bug-Url: https://bugzilla.redhat.com/1094144
Signed-off-by: Maor Lipchuk <mlipchuk@redhat.com>
core: Use validation only if Template is not blank

The validation of, same DC when creating a VM from a Template,
should only be validated when creating a VMs which does not have
Blank Template as their based on image.

Blank Template is the default Template for every new created VM, and it is
hosted on the default Data Center

Change-Id: I06a0c911c50f6ff25d9dca358c6a199fa0cdbb59
Bug-Url: https://bugzilla.redhat.com/1125196
Signed-off-by: Maor Lipchuk <mlipchuk@redhat.com>