shelve: remove a bundlerepo method

shelve: remove a bundlerepo method

It was added in 43816070284e (shelve: add a bundlerepo method,
2014-10-10), but I haven't been able to find a place it was used.

Differential Revision: https://phab.mercurial-scm.org/D9696

--- a/mercurial/shelve.py	Fri Jan 08 16:38:41 2021 -0800
+++ b/mercurial/shelve.py	Thu Jan 07 12:37:14 2021 -0800
@@ -38,7 +38,6 @@
 from . import (
     bookmarks,
     bundle2,
-    bundlerepo,
     changegroup,
     cmdutil,
     discovery,
@@ -149,12 +148,6 @@
         finally:
             fp.close()
 
-    def bundlerepo(self):
-        path = self.vfs.join(self.fname)
-        return bundlerepo.instance(
-            self.repo.baseui, b'bundle://%s+%s' % (self.repo.root, path), False
-        )
-
     def writebundle(self, bases, node):
         cgversion = changegroup.safeversion(self.repo)
         if cgversion == b'01':