Add printf attribute to log_err/DPRINTF and fix a few warnings

Modified to not use %z for portability reasons.

scanner.c

@@ -861,7 +861,7 @@ start_scanner()
 		fill_playlists();
 	}
 
-	DPRINTF(E_DEBUG, L_SCANNER, "Initial file scan completed\n", DB_VERSION);
+	DPRINTF(E_DEBUG, L_SCANNER, "Initial file scan completed\n");
 	//JM: Set up a db version number, so we know if we need to rebuild due to a new structure.
 	sql_exec(db, "pragma user_version = %d;", DB_VERSION);
 }