query_classifier.cc: set_query_type lost previous query type if the new was more restrictive. Problem was that if query is both READ and SESSION_WRITE and configuration parameter use_sql_variables_in=all was set, routing target became ambiguous. Replaced call to set_query_type with simply adding new type to type (=bit field) and checking unsupported combinations in readwritesplit.c:get_route_target. If such a case is met, a detailed error is written to error log in readwritesplit.c. mysql_client.c sees the error code and sends an error to client. Then mysql_client.c calls router's handleError which ensures that there are enough backend servers so that the session can continue.
When no users are loaded from backends, instead of counting it as a failure the service is started and the next time a client connects an attempt to load the users from the backends is made.
Added a header which contains the locations for the testing directory and its subfolders which enables
the test to write into the right logfiles. Also added a calls to skygw_log_sync_all before assertions
forcing all logs to be written to disk at the time the test might fail.
service.h:Added the 'serviceStartFailed' function which tries to start services with successfully started routers but no successfully started listeners.
mysql_mon.c:Added a call to ServiceStartFailed when servers come available.
readwritesplit.c:route_session_write failed if the last backend on all backends list was not in use. THe situation where not all backends are used by routing session is normal especially if max_slave_connections is not set to 100%. Thus session commands may have failed if user was bit unlucky.
Changed the logic so that the function fails (and session is closed) if routing fails to any such backend which is in use in the session.
Added server references to services instead of using a raw pointers to server instances.
Changed all references to service->database to service->dbref.
tee.c:routeQuery cloned partial MySQL packets to be routed to child router. Problems were due to the use of gwbuf_clone and modutil_MySQL_query which clone/examine only the first buffer from the buffer list which composes GWBUF.
modutil.c: Added function modutil_MySQL_query_len which calculates MySQL packet length and the missing bytecount
