Exclude multimaster from windows build

Author: vbwagner

src/tools/msvc/Mkvcbuild.pm

@@ -53,7 +53,7 @@ my @contrib_excludes = (
 	'ltree_plpython',  'pgcrypto',
 	'sepgsql',         'brin',
 	'test_extensions', 'test_pg_dump',
-	'pg_probackup',
+	'pg_probackup', 'mmts', 'referee',
 	'snapshot_too_old');
 
 # Set of variables for frontend modules