BUILD: log: silent build warnings due to unchecked __objt_{server,applet}

These ones are safe to use there since the same check is performed in
the switch/case they're used it. Let's use the unguarded versions
instead.
diff --git a/src/log.c b/src/log.c
index 33586cf..32308fa 100644
--- a/src/log.c
+++ b/src/log.c
@@ -2016,10 +2016,10 @@
 			case LOG_FMT_SERVER: // %s
 				switch (obj_type(s ? s->target : NULL)) {
 				case OBJ_TYPE_SERVER:
-					src = objt_server(s->target)->id;
+					src = __objt_server(s->target)->id;
 					break;
 				case OBJ_TYPE_APPLET:
-					src = objt_applet(s->target)->name;
+					src = __objt_applet(s->target)->name;
 					break;
 				default:
 					src = "<NOSRV>";