Playlist Catalogue: fix: "Save Current Playlist" may fail silently

- After rebooting, unless the current playlist
had been manually resumed already, the "Save
Current Playlist" option in the root menu's/
playlist catalogue's context menu failed to work.

- Eliminate error message attempting to view current
playlist when no control file present.

Change-Id: I58f1d3dc6f256fcee106ff5a17f69fa46d67b2e4

apps/playlist_viewer.c

@@ -387,7 +387,7 @@ static bool playlist_viewer_init(struct playlist_viewer * viewer,
     if (!filename && !is_playing)
     {
         /* Try to restore the list from control file */
-        if (playlist_resume() == -1)
+        if (!file_exists(PLAYLIST_CONTROL_FILE) || playlist_resume() == -1)
         {
             /* Nothing to view, exit */
             splash(HZ, ID2P(LANG_CATALOG_NO_PLAYLISTS));