query_classifier.cc:skygw_get_canonical: Fixed bug in how strings were passed to replace_literal function. Changed to use item->str_ptr which stores all strings in the same way unlike item->name in which some string values have double quotation.
skygw_utils.cc:Fixed regexp so that it detects literals at the end of line too.
Fixed various memory leaks

dbuser.c: key.user value was never freed
skygw_utils.cc: replace_literal values were not always freed
Merge remote-tracking branch 'origin/Z3' into MAX-237