[tracker] Fix "void function should not return a value"

[Ting-Wei Lan <lantw src gnome org>]

commit 4835e9e06cf1320f74b7975724753ae1afd17711
Author: Ting-Wei Lan <lantw src gnome org>
Date:   Wed Mar 18 15:12:55 2015 +0800

    Fix "void function should not return a value"
    
    https://bugzilla.gnome.org/show_bug.cgi?id=746381

 src/libtracker-miner/tracker-file-notifier.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/libtracker-miner/tracker-file-notifier.c b/src/libtracker-miner/tracker-file-notifier.c
index b5054ea..5abe9d3 100644
--- a/src/libtracker-miner/tracker-file-notifier.c
+++ b/src/libtracker-miner/tracker-file-notifier.c
@@ -1732,8 +1732,8 @@ tracker_file_notifier_invalidate_file_iri (TrackerFileNotifier *notifier,
        TrackerFileNotifierPrivate *priv;
        GFile *canonical;
 
-       g_return_val_if_fail (TRACKER_IS_FILE_NOTIFIER (notifier), NULL);
-       g_return_val_if_fail (G_IS_FILE (file), NULL);
+       g_return_if_fail (TRACKER_IS_FILE_NOTIFIER (notifier));
+       g_return_if_fail (G_IS_FILE (file));
 
        priv = notifier->priv;
        canonical = tracker_file_system_get_file (priv->file_system,