changegroup: exclude submanifests from manifest progress

The progress callback for manifests is cleared outside of
_unpackmanifests(), which means it will remain in effect while pulling
subdirectory manifests when using treemanifests. Since the total
number of revisions used for the progress is the number of changesets,
the total number of treemanifest revisions is usually larger than
that. One effect of this is that the ETA is negative. It's hard to
estimate the number of subdirectory revisions, so let's just exclude
them from progress for now.

mercurial/changegroup.py

@@ -306,6 +306,7 b' class cg1unpacker(object):'
         self.manifestheader()
         repo.manifest.addgroup(self, revmap, trp)
         repo.ui.progress(_('manifests'), None)
+        self.callback = None
 
     def apply(self, repo, srctype, url, emptyok=False,
               targetphase=phases.draft, expectedtotal=None):
@@ -393,7 +394,6 b' class cg1unpacker(object):'
 
                 # process the files
                 repo.ui.status(_("adding file changes\n"))
-                self.callback = None
                 pr = prog(_('files'), efiles)
                 newrevs, newfiles = _addchangegroupfiles(
                     repo, self, revmap, trp, pr, needfiles)