ocarina: Reset album art when new song loaded

I set it to the ocarina logo, it can change again later.

ocarina/body/footer/nowplaying.py

@@ -78,4 +78,5 @@ def on_load(title, artist, album, year, lenstr, count):
 	YEAR.set_text("Year: %s" % year)
 	LENGTH.set_text("Length: %s" % lenstr)
 	COUNT.set_text("Play count: %s" % count)
+	set_art("images/ocarina.png")
 	on_like()