[tracker] libtracker-miner: Check the crawler cancellable before destroying it

[Carlos Garnacho <carlosg src gnome org>]

commit ccfa7a783313d66bc17278f7be36168a14196a63
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Aug 19 23:38:03 2015 +0200

    libtracker-miner: Check the crawler cancellable before destroying it
    
    It won't be set unless tracker_crawler_start() was called, so there's a
    chance it could be NULL on finalize. Spotted on make distcheck

 src/libtracker-miner/tracker-crawler.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/src/libtracker-miner/tracker-crawler.c b/src/libtracker-miner/tracker-crawler.c
index ba58193..900af77 100644
--- a/src/libtracker-miner/tracker-crawler.c
+++ b/src/libtracker-miner/tracker-crawler.c
@@ -305,8 +305,10 @@ crawler_finalize (GObject *object)
                g_source_remove (priv->idle_id);
        }
 
-       g_cancellable_cancel (priv->cancellable);
-       g_object_unref (priv->cancellable);
+       if (priv->cancellable) {
+               g_cancellable_cancel (priv->cancellable);
+               g_object_unref (priv->cancellable);
+       }
 
        g_queue_foreach (priv->directories, (GFunc) directory_root_info_free, NULL);
        g_queue_free (priv->directories);