webadmin: Disable static IP if equal to hostname

This to prevent a user from performing a move that would necessarily
cause the engine to lost connectivity to a host.

Change-Id: I46836fac331f3d510fc3be8d435bb71fb546d37c
Bug-Url: https://bugzilla.redhat.com/989360
Signed-off-by: Lior Vernia <lvernia@redhat.com>