shared/timeout-glib: Check 0 id when removing timeout

If the id is 0 that makes it is invalid already.
diff --git a/src/shared/timeout-glib.c b/src/shared/timeout-glib.c
index 4163bce..fd71ca4 100644
--- a/src/shared/timeout-glib.c
+++ b/src/shared/timeout-glib.c
@@ -71,8 +71,12 @@
 
 void timeout_remove(unsigned int id)
 {
-	GSource *source = g_main_context_find_source_by_id(NULL, id);
+	GSource *source;
 
+	if (!id)
+		return;
+
+	source = g_main_context_find_source_by_id(NULL, id);
 	if (source)
 		g_source_destroy(source);
 }