Description of problem:
python-dateutil got updated to a newer version than nikola is happy with.

Version-Release number of selected component (if applicable):
python-nikola-7.3.0-5.fc22.noarch

$ nikola3.4 
Traceback (most recent call last):
  File "/usr/lib/python3.4/site-packages/pkg_resources/__init__.py", line 651, in _build_master
    ws.require(__requires__)
  File "/usr/lib/python3.4/site-packages/pkg_resources/__init__.py", line 952, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/usr/lib/python3.4/site-packages/pkg_resources/__init__.py", line 844, in resolve
    raise VersionConflict(dist, req).with_context(dependent_req)
pkg_resources.ContextualVersionConflict: (python-dateutil 2.4.2 (/usr/lib/python3.4/site-packages), Requirement.parse('python-dateutil==2.4.0'), {'Nikola'})

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/bin/nikola3.4", line 5, in <module>
    from pkg_resources import load_entry_point
  File "/usr/lib/python3.4/site-packages/pkg_resources/__init__.py", line 3084, in <module>
    @_call_aside
  File "/usr/lib/python3.4/site-packages/pkg_resources/__init__.py", line 3070, in _call_aside
    f(*args, **kwargs)
  File "/usr/lib/python3.4/site-packages/pkg_resources/__init__.py", line 3097, in _initialize_master_working_set
    working_set = WorkingSet._build_master()
  File "/usr/lib/python3.4/site-packages/pkg_resources/__init__.py", line 653, in _build_master
    return cls._build_from_requirements(__requires__)
  File "/usr/lib/python3.4/site-packages/pkg_resources/__init__.py", line 666, in _build_from_requirements
    dists = ws.resolve(reqs, Environment())
  File "/usr/lib/python3.4/site-packages/pkg_resources/__init__.py", line 839, in resolve
    raise DistributionNotFound(req, requirers)
pkg_resources.DistributionNotFound: The 'python-dateutil==2.4.0' distribution was not found and is required by Nikola

$ nikola
Traceback (most recent call last):
  File "/usr/bin/nikola", line 5, in <module>
    from pkg_resources import load_entry_point
  File "/usr/lib/python2.7/site-packages/pkg_resources/__init__.py", line 3084, in <module>
    @_call_aside
  File "/usr/lib/python2.7/site-packages/pkg_resources/__init__.py", line 3070, in _call_aside
    f(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/pkg_resources/__init__.py", line 3097, in _initialize_master_working_set
    working_set = WorkingSet._build_master()
  File "/usr/lib/python2.7/site-packages/pkg_resources/__init__.py", line 653, in _build_master
    return cls._build_from_requirements(__requires__)
  File "/usr/lib/python2.7/site-packages/pkg_resources/__init__.py", line 666, in _build_from_requirements
    dists = ws.resolve(reqs, Environment())
  File "/usr/lib/python2.7/site-packages/pkg_resources/__init__.py", line 839, in resolve
    raise DistributionNotFound(req, requirers)
pkg_resources.DistributionNotFound: The 'python-dateutil==2.4.0' distribution was not found and is required by Nikola