Fixes to Coverity issues 84388, 84386, 84385

mysql_mon.c: Added back server state logging to Debug build.
query_classifier.cc: removed some extra debug code, cleaned up a bit function documentation.
mysql_client_server_protocol.h, mysql_backend.c, mysql_common.c: changed some variables to signed ones to enable checking of calculations in the code.
skygw_utils.cc: removed erroneous debug assertion.
Merge branch 'release-1.0GA' of https://github.com/mariadb-corporation/MaxScale into release-1.0GA