unit_test.c: close va_list before return

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>

test/unit_test.c

@@ -579,8 +579,11 @@ static void test_mg_websocket_client_connect(int use_ssl) {
 
 static int alloc_printf(char **buf, size_t size, char *fmt, ...) {
     va_list ap;
+    int ret = 0;
     va_start(ap, fmt);
-    return alloc_vprintf(buf, size, fmt, ap);
+    ret = alloc_vprintf(buf, size, fmt, ap);
+    va_end(ap);
+    return ret:
 }
 
 static void test_mg_upload(void) {