Fixes to Coverity issues 77197 (mysql_common.c, dcb.c, mysql_client.c, skygw_debug.h), 72654 (poll.c), 72756 (mysql_backend.c), 72744 (mysql_backend.c), 77197 (mysql_common.c), 72746 (mysql_common.c), 72676 (mysql_common.c), 72705 (readwritesplit.c), 72697 (readwritesplit.c), 72652 (skygw_debug.h)
Addition to previous fix
Merge branch 'develop' of https://github.com/mariadb-corporation/MaxScale into develop
Removed unnecessary local variables for errno since it is thread safe.