engine: event on interface status change

When the status of the interface/bond is changed an event should be
reported in the following cases-
1. There is a network or label on the interface/bond
2. The interface is a slave of a bond and 1 is true for the parent bond.

There won't be more than one event per interface each 30 minutes.

Change-Id: I76953e4b52e35d2e18b6bc68051fa7dd6f3db129
Bug-Url: https://bugzilla.redhat.com/1079719
Bug-Url: https://bugzilla.redhat.com/987299
Signed-off-by: Alona Kaplan <alkaplan@redhat.com>