Fix minor memory leaks

The main function and monitor creation both leaked a few bytes of memory.

server/core/gateway.cc

@@ -2084,6 +2084,8 @@ return_main:
         write_child_exit_code(daemon_pipe[1], rc);
     }
 
+    MXS_FREE(cnf_file_arg);
+
     if (threads)
     {
         MXS_FREE(threads);

server/core/monitor.c

@@ -94,7 +94,7 @@ monitor_alloc(char *name, char *module)
     }
     mon->state = MONITOR_STATE_ALLOC;
     mon->name = name;
-    mon->module_name = module;
+    mon->module_name = my_module;
     mon->handle = NULL;
     mon->databases = NULL;
     *mon->password = '\0';