[Fix] Fix race condition on maps reinit

src/rspamd.c

 		REF_RELEASE (tmp_cfg);
 	}
 	else {
-		rspamd_map_preload (rspamd_main->cfg);
 		msg_info_main ("replacing config");
 		REF_RELEASE (old_cfg);
 		msg_info_main ("config has been reread successfully");
+		rspamd_map_preload (rspamd_main->cfg);
 	}
 }