Control resource extension process defining required extensions

Blueprint l3-ext-gw-modes

The resource extension process is slightly altered so that an
API extension can specify which extensions should be processed before
its attributes can be processed. This is needed to ensure the
l3-ext-gw-mode API extension sets up correctly validators and other
attributes for the external_gateway_info attribute

Change-Id: I7c05746e67b1324a73082dde8b5c862d631c083c
Fix pool update error in lbaas

fixes bug 1185687

Do not notify namespace agent of modified pool
if pool doesn't have vip

Change-Id: Ibe3399aaa145d19fc758f08adb51c7ffefa5bb3a
Fix Cisco nexus plugin failure for first VLAN on phy interface

Fixes bug 1174852

This fix changes the command being sent to the Nexus switch for
enabling a VLAN on an interface such that the 'add' keyword is
included only when there are prior VLANs already enabled on that
interface.

Change-Id: I466bcb839912b164b84be0e6721d87206c0e53eb
Merge "Fix pool update error in lbaas"
Merge "Fix Cisco nexus plugin failure for first VLAN on phy interface"
Merge "Control resource extension process defining required extensions"