sync: Correctly sync multi manifest workspaces

When actually fetching the manifests, start at the correct (sub)
manifest.

Bug: https://crbug.com/gerrit/16198
Change-Id: I39fdd726f1917ef4277a0b7c83663c8f49167466
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/343914
Tested-by: LaMont Jones <lamontjones@google.com>
Reviewed-by: Mike Frysinger <vapier@google.com>

subcmds/sync.py

diff --git a/subcmds/sync.py b/subcmds/sync.py
index a2b376b..de4ac3a 100644
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@@ -1071,14 +1071,13 @@
               file=sys.stderr)
 
     for m in self.ManifestList(opt):
-      mp = m.manifestProject
-      is_standalone_manifest = bool(mp.standalone_manifest_url)
-      if not is_standalone_manifest:
-        mp.PreSync()
+      if not m.manifestProject.standalone_manifest_url:
+        m.manifestProject.PreSync()
 
-      if opt.repo_upgraded:
-        _PostRepoUpgrade(m, quiet=opt.quiet)
+    if opt.repo_upgraded:
+      _PostRepoUpgrade(manifest, quiet=opt.quiet)
 
+    mp = manifest.manifestProject
     if opt.mp_update:
       self._UpdateAllManifestProjects(opt, mp, manifest_name)
     else: