libsaria: Catch errors when writing cache files

The user doesn't want to see these...

libsaria/storage/cache.py

@@ -27,9 +27,12 @@ def make_cache_path(artist, album, file):
 def fill_cache(artist, album, title, cache_func, cache_path):
 	text = cache_func(artist, album, title)
 	if text != None:
-		f = open(cache_path, 'w')
-		f.write(text)
-		f.close()
+		try:
+			f = open(cache_path, 'w')
+			f.write(text)
+			f.close()
+		except:
+			pass
 		return True
 	return False