Log: skygw_log_flush replaced with mxs_log_flush.

skygw_log_flush replaced with mxs_log_flush and skygw_log_sync_all
with mxs_log_flush_sync.

server/modules/filter/dbfwfilter.c

@@ -2231,7 +2231,7 @@ int main(int argc, char** argv)
 	printf("Failed to parse rule. Read the error log for the reason of the failure.\n");
     }
 
-    skygw_log_sync_all();
+    mxs_log_flush_sync();
 
     return 0;
 }