HBase Thrift SPNEGO configs should not be required. The `hbase.thrift.spnego.keytab.file` and `hbase.thrift.spnego.principal` configs should fall back to the `hbase.thrift.keytab.file` and `hbase.thrift.kerberos.principal` configs. This will avoid any issues during upgrades. Signed-off-by: Josh Elser <elserj@apache.org> Amending-author: Josh Elser <elserj@apache.org> Closes #850