* HBASE-23275: Track active master's address in ActiveMasterManager Currently we just track whether an active master exists. It helps to also track the address of the active master in all the masters to help serve the client RPC requests to know which master is active. Signed-off-by: Nick Dimiduk <ndimiduk@apache.org> Signed-off-by: Andrew Purtell <apurtell@apache.org>