Adds 'raw' assigns and unassigns methods to Hbck Service. Fixes HbckService so it works when cluster is Kerberized.
This module has proto files used by core. These protos overlap with protos that are used by coprocessor endpoints (CPEP) in the module hbase-protocol. So core versions have a different name, the generated classes are relocated -- i.e. shaded -- to a new location; they are moved from org.apache.hadoop.hbase.* to org.apache.hadoop.hbase.shaded.