Do not remove issue from branch after it is landed manually

git_cl.py

 #!/usr/bin/env python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Copyright (C) 2008 Evan Martin <martine@danga.com>
 
 """A git-command for integrating reviews on Rietveld and Gerrit."""
 
 from __future__ import print_function
@@ skipping 4079 matching lines @@
     cl.CloseIssue()
     props = cl.GetIssueProperties()
     patch_num = len(props['patchsets'])
     comment = "Committed patchset #%d (id:%d)%s manually as %s" % (
         patch_num, props['patchsets'][-1], to_pending, revision)
     if options.bypass_hooks:
       comment += ' (tree was closed).' if GetTreeStatus() == 'closed' else '.'
     else:
       comment += ' (presubmit successful).'
     cl.RpcServer().add_comment(cl.GetIssue(), comment)
-    cl.SetIssue(None)
 
   if pushed_to_pending:
     _, branch = cl.FetchUpstreamTuple(cl.GetBranch())
     print('The commit is in the pending queue (%s).' % pending_ref)
     print('It will show up on %s in ~1 min, once it gets a Cr-Commit-Position '
           'footer.' % branch)
 
   hook = POSTUPSTREAM_HOOK_PATTERN % cmd
   if os.path.isfile(hook):
     RunCommand([hook, merge_base], error_ok=True)
@@ skipping 968 matching lines @@
 if __name__ == '__main__':
   # These affect sys.stdout so do it outside of main() to simplify mocks in
   # unit testing.
   fix_encoding.fix_encoding()
   setup_color.init()
   try:
     sys.exit(main(sys.argv[1:]))
   except KeyboardInterrupt:
     sys.stderr.write('interrupted\n')
     sys.exit(1)