get ready for change that happened in 2.1 with respect to rpc change

RELEASE_NOTES

src/common/slurm_protocol_util.c

src/common/slurmdbd_defs.c

src/common/slurmdbd_defs.h

...ugins/accounting_storage/mysql/accounting_storage_mysql.c

...ugins/accounting_storage/mysql/accounting_storage_mysql.h

src/plugins/accounting_storage/mysql/mysql_cluster.c

src/plugins/accounting_storage/mysql/mysql_job.c

src/plugins/accounting_storage/mysql/mysql_job.h