Fix to not send fdb updates when no port changes

(cherry picked from commit 28054a62314daaf30f636e4989cded529b6f12d5)
Fixes bug: 1241874

Change-Id: I36d453c01301ce0b04f64e719ff8f2fe55c72fa2
Fix lb doesn't remove vxlan int. if no int. map

LinuxBridge agent doesn't remove vxlan interfaces
if interface_mappings is not set.

(cherry picked from commit f39c8965d9679971afa3db101c09ca2740b39a91)
Fixes bug: 1240742

Change-Id: I163f1ac8cbd46b8d8836152e2be8cb7608a8ca22
Merge "Fix to not send fdb updates when no port changes" into stable/havana
Merge "Fix lb doesn't remove vxlan int. if no int. map" into stable/havana