certbot: Missing versioned dependency on python-psutil

[Arto Jantunen <viiru@debian.org>]

The backported certbot package is missing a versioned dependency on a
backported python-psutil:

# /usr/bin/certbot -q renew
Traceback (most recent call last):
  File "/usr/bin/certbot", line 5, in <module>
    from pkg_resources import load_entry_point
  File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 2876, in <module>
    working_set = WorkingSet._build_master()
  File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 451, in _build_master
    return cls._build_from_requirements(__requires__)
  File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 464, in _build_from_requirements
    dists = ws.resolve(reqs, Environment())
  File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 639, in resolve
    raise DistributionNotFound(req)
pkg_resources.DistributionNotFound: psutil>=2.2.1

-- 
Arto Jantunen