[tracker-miners] tracker-extract-mp3: Always initialise g_autofree/g_autoptr variables

[Sam Thursfield <sthursfield src gnome org>]

commit ff4041e4d773fe2968086f3079bd54a24e95662e
Author: Sam Thursfield <sam afuera me uk>
Date:   Tue Jun 30 00:06:12 2020 +0200

    tracker-extract-mp3: Always initialise g_autofree/g_autoptr variables
    
    We risk a call to free() with a random pointer if we don't set these
    to NULL initially.

 src/tracker-extract/tracker-extract-mp3.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/src/tracker-extract/tracker-extract-mp3.c b/src/tracker-extract/tracker-extract-mp3.c
index 2f8242078..4dcf6107a 100644
--- a/src/tracker-extract/tracker-extract-mp3.c
+++ b/src/tracker-extract/tracker-extract-mp3.c
@@ -2867,8 +2867,8 @@ tracker_extract_get_metadata (TrackerExtractInfo *info)
        }
 
        if (md.mb_recording_id) {
-               g_autofree char *mb_recording_uri;
-               g_autoptr(TrackerResource) mb_recording;
+               g_autofree char *mb_recording_uri = NULL;
+               g_autoptr(TrackerResource) mb_recording = NULL;
 
                mb_recording_uri = g_strdup_printf("https://musicbrainz.org/recording/%s";, 
md.mb_recording_id);
                mb_recording = tracker_extract_new_external_reference("https://musicbrainz.org/doc/Recording";,
@@ -2878,8 +2878,8 @@ tracker_extract_get_metadata (TrackerExtractInfo *info)
        }
 
        if (md.mb_track_id) {
-               g_autofree char *mb_track_uri;
-               g_autoptr(TrackerResource) mb_track;
+               g_autofree char *mb_track_uri = NULL;
+               g_autoptr(TrackerResource) mb_track = NULL;
 
                mb_track_uri = g_strdup_printf("https://musicbrainz.org/track/%s";, md.mb_track_id);
                mb_track = tracker_extract_new_external_reference("https://musicbrainz.org/doc/Track";,