revset: remove a rare usage of "%d" for a non-revision item

In order to fix an important bug, we are about to narrow the semantic of "%d"
in revset. This is one of the few exceptions that we need to get rid of before
being able to fix the bug.

See the later semantic narrowing changeset for full rationale on the semantic
change.

mercurial/wireprotov2server.py

@@ -823,7 +823,7 b' def resolvenodes(repo, revisions):'
                         '%s key not present in changesetexplicitdepth revision '
                         'specifier', (key,))
 
-            for rev in repo.revs(b'ancestors(%ln, %d)', spec[b'nodes'],
+            for rev in repo.revs(b'ancestors(%ln, %s)', spec[b'nodes'],
                                  spec[b'depth'] - 1):
                 node = cl.node(rev)