grilo: Push up last.fm art rank

Last.fm started to use https, making it fit to be a media art provider
again. Spotify started to require authentication for art retrieval,
lowering it relevance.

gnomemusic/grilo.py

@@ -35,8 +35,8 @@ import os
 os.environ['GRL_PLUGIN_RANKS'] = ("grl-local-metadata:5,"
                                   "grl-filesystem:4,"
                                   "grl-tracker-source:3,"
-                                  "grl-spotify-cover:2,"
-                                  "grl-lastfm-cover:1")
+                                  "grl-lastfm-cover:2,"
+                                  "grl-spotify-cover:1")
 from gi.repository import Grl
 logger = logging.getLogger(__name__)