Fix to bug #613, http://bugs.skysql.com/show_bug.cgi?id=613
Simple fix: disable logging to files where logging fails.
Addition to fix to bug #613, http://bugs.skysql.com/show_bug.cgi?id=613
Added new declaration of skygw_file_write and modification to the function which returns errno instead of boolean.
Fix to bug #614, http://bugs.skysql.com/show_bug.cgi?id=614
Added protected state check to mysql_client.c, fixed locking in session.c
readwritesplit.c: prevent switching the master during session. Added logging to cases where master has changed.
Moved DCB's member errhandle_called behing DEBUG flags to Release build. It shows if handleError is called for a DCB and makes it possible to avoid redundant calls.
Merge branch 'develop' of https://github.com/mariadb-corporation/MaxScale into develop