archival: use walk() instead of matches() on manifest

All we care about is the filepaths, so this avoids a pointless copy of the
manifest that we only used to extract matching filenames.

Differential Revision: https://phab.mercurial-scm.org/D8090

mercurial/archival.py

@@ -355,7 +355,7 b' def archive('
         if match(name):
             write(name, 0o644, False, lambda: buildmetadata(ctx))
 
-    files = [f for f in ctx.manifest().matches(match)]
+    files = list(ctx.manifest().walk(match))
     total = len(files)
     if total:
         files.sort()