Part of MDEV-13073 AliSQL Optimize performance of semisync

Did the following renames to match other similar variables
key_ss_mutex_LOCK_binlog_       > key_LOCK_bing
key_ss_cond_COND_binlog_send_  -> key_COND_binlog_send
COND_binlog_send_              -> COND_binlog_send
LOCK_binlog_                   -> LOCK_binlog

debian/mariadb-server-10.2.install does not install semisync libs.