[mpd] Return the correct values for number of songs, artists, albums and

song length sum in the "stats" command (wrong values are still reported
for uptime, db_update and playtime)

src/db.h

@@ -416,6 +416,12 @@ db_query_fetch_string_sort(struct query_params *qp, char **string, char **sortst
 int
 db_files_get_count(void);
 
+int
+db_files_get_artist_count(void);
+
+int
+db_files_get_album_count(void);
+
 int
 db_files_get_count_bymatch(char *path);