kernel - Major bridging functionality added (bug fixes 6)

kernel - Major bridging functionality added (bug fixes 6)

* Flapping on one of the member interfaces can cause the entire bridge
  to go down due to all member interfaces entering a transient state.
  For example, if openvpn is flapping the related tap interfaces will
  go up and down without any actual packet traffic making it across.

  With these changes openvpn flapping no longer makes the bridge
  effectively non-operational.

* When a port is disabled or enabled either manually or due to a TAP
  process going away / attaching, only issue a configuration update
  when transitioning out of an active state.

  Thus disabled<->l1blocking flip-flopping does not cause the other
  member interfaces to change state.

* Also change the initial state setup when LINK1 is flagged.
  Go into the L1BLOCKING state instead of the BLOCKING state.