[tracker] tracker-extract-mp3: Use performer as fallback to album artist

[Carlos Garnacho <carlosg src gnome org>]

commit 6dc2c85856126c97277b83b2a17122581d1122cc
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sat May 21 23:21:51 2016 +0200

    tracker-extract-mp3: Use performer as fallback to album artist
    
    Commit 79af6adf6 changed the MP3 extractor to use the TPE2 tag info
    to retrieve nmm:albumArtist. It is fine to favor that data, but we
    should still resort to TPE1 if we get nothing from there. Otherwise
    the album artist is not filled.

 src/tracker-extract/tracker-extract-mp3.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/src/tracker-extract/tracker-extract-mp3.c b/src/tracker-extract/tracker-extract-mp3.c
index 8a78a19..a3e090e 100644
--- a/src/tracker-extract/tracker-extract-mp3.c
+++ b/src/tracker-extract/tracker-extract-mp3.c
@@ -2374,9 +2374,10 @@ tracker_extract_get_metadata (TrackerExtractInfo *info)
                                               md.id3v22.performer2,
                                               md.id3v1.artist);
 
-       md.album_artist = tracker_coalesce_strip (3, md.id3v24.performer2,
+       md.album_artist = tracker_coalesce_strip (4, md.id3v24.performer2,
                                                  md.id3v23.performer2,
-                                                 md.id3v22.performer2);
+                                                 md.id3v22.performer2,
+                                                 md.performer);
 
        md.album = tracker_coalesce_strip (4, md.id3v24.album,
                                           md.id3v23.album,