repair: clean up stale lock file from store backup

Since we did a directory rename on the stores, the source
repository's lock path now references the dest repository's
lock path and the dest repository's lock path now references
a non-existent filename.

So releasing the lock on the source will unlock the dest and
releasing the lock on the dest will no-op because it fails due
to file not found. So we clean up the dest's lock manually.

mercurial/repair.py

@@ -918,6 +918,12 b' def _upgraderepo(ui, srcrepo, dstrepo, r'
                'again\n'))
     scmutil.writerequires(srcrepo.vfs, requirements)
 
+    # The lock file from the old store won't be removed because nothing has a
+    # reference to its new location. So clean it up manually. Alternatively, we
+    # could update srcrepo.svfs and other variables to point to the new
+    # location. This is simpler.
+    backupvfs.unlink('store/lock')
+
     return backuppath
 
 def upgraderepo(ui, repo, run=False, optimize=None):

tests/test-upgrade-repo.t

@@ -303,7 +303,6 b' old store should be backed up'
   00manifest.i
   data
   fncache
-  lock
   phaseroots
   undo
   undo.backup.fncache