Automatic merge from submit-queue
LBaaS v2 Support for Openstack Cloud Provider Plugin
Resolves#19774.
This work is based on Gophercloud support for LBaaS v2 currently in review (this will have to merge first):
https://github.com/rackspace/gophercloud/pull/575
These changes includes the addition of a new loadbalancer configuration option: **LBVersion**. If this configuration attribute is missing or anything other than "v2", lbaas v1 implementation will be used.