Fix randomisation algorithm. Thanks to jawbroken on IRC.

src/playlist/sort.c

@@ -146,7 +146,7 @@ void playlist_ItemArraySort( unsigned i_items, playlist_item_t **pp_items,
 
         for( i_position = i_items - 1; i_position > 0; i_position-- )
         {
-            i_new = rand() % i_position;
+            i_new = rand() % (i_position+1);
             p_temp = pp_items[i_position];
             pp_items[i_position] = pp_items[i_new];
             pp_items[i_new] = p_temp;