MXS-1389: Fix rule reloading and query parsing requirements

Reloading of rules now properly uses the current rule file if no argument
was provided. The rule version counter also used atomic operations for the
sake of correctness.

The rule parsing is now only required for DML type statements that should
be fully parsed.

maxscale-system-test/fwf_reload.cpp

@@ -20,7 +20,7 @@ int main(int argc, char *argv[])
     char rules_dir[4096];
 
     sprintf(rules_dir, "%s/fw/", test_dir);
-    int N = 10;
+    int N = 12;
     int i;
 
     Test->stop_maxscale();