client: Fix use of g_free

g_free shall only be used with pointer allocated with g_* functions.
diff --git a/src/adapter.c b/src/adapter.c
index c1c792a..390216a 100644
--- a/src/adapter.c
+++ b/src/adapter.c
@@ -1416,7 +1416,7 @@
 	if (!discovery_filter)
 		return;
 
-	g_slist_free_full(discovery_filter->uuids, g_free);
+	g_slist_free_full(discovery_filter->uuids, free);
 	g_free(discovery_filter);
 }