Recompute all songalbumids at startup

Due to the two Murmur64 implementations for 64 and 32bit machines, the
hash is not compatible when moving the SQLite DB between 32/64 bit hosts.

So we'll recompute all the songalbumids at startup, just in case.

src/db.h

@@ -289,6 +289,9 @@ db_query_fetch_string(struct query_params *qp, char **string);
 int
 db_files_get_count(void);
 
+void
+db_files_update_songalbumid(void);
+
 void
 db_file_inc_playcount(int id);