[PATCH 0 of 1] Fix traceback in hgext/gpg.py

[Giorgos Keramidas]

In crew:edd676eae7d7 the gpg extension throws a traceback when run on
the Mercurial crew repository itself:

** unknown exception encountered, details follow
** report bug details to http://www.selenic.com/mercurial/bts
** or mercurial at selenic.com
** Mercurial Distributed SCM (version 11ce115a1203)
** Extensions loaded: alias, bookmarks, convert, extdiff, gpg, graphlog, mq, notify, patchbomb, record, transplant, purge, rebase, churn
Traceback (most recent call last):
  File "/usr/local/bin/hg", line 27, in <module>
    mercurial.dispatch.run()
  File "/usr/local/lib/python2.5/site-packages/mercurial/dispatch.py", line 16, in run
    sys.exit(dispatch(sys.argv[1:]))
  File "/usr/local/lib/python2.5/site-packages/mercurial/dispatch.py", line 27, in dispatch
    return _runcatch(u, args)
  File "/usr/local/lib/python2.5/site-packages/mercurial/dispatch.py", line 43, in _runcatch
    return _dispatch(ui, args)
  File "/usr/local/lib/python2.5/site-packages/mercurial/dispatch.py", line 378, in _dispatch
    return runcommand(lui, repo, cmd, fullargs, ui, options, d)
  File "/usr/local/lib/python2.5/site-packages/mercurial/dispatch.py", line 249, in runcommand
    ret = _runcommand(ui, options, cmd, d)
  File "/usr/local/lib/python2.5/site-packages/mercurial/dispatch.py", line 430, in _runcommand
    return checkargs()
  File "/usr/local/lib/python2.5/site-packages/mercurial/dispatch.py", line 383, in checkargs
    return cmdfunc()
  File "/usr/local/lib/python2.5/site-packages/mercurial/dispatch.py", line 377, in <lambda>
    d = lambda: util.checksignature(func)(ui, *args, **cmdoptions)
  File "/usr/local/lib/python2.5/site-packages/mercurial/util.py", line 584, in check
    return func(*args, **kwargs)
  File "/usr/local/lib/python2.5/site-packages/hgext/gpg.py", line 155, in sigs
    for rev in reversed(revs):
TypeError: argument to reversed() must be a sequence