Description of problem:
The pytest executable does not run.

Version-Release number of selected component (if applicable):
python-logilab-common-0.53.0-2.fc15.noarch

Steps to Reproduce:
1. install python-logilab-common
2. run in a terminal
 $ pytest
  
Actual results:
$ pytest
Traceback (most recent call last):
  File "/usr/bin/pytest", line 3, in <module>
    from logilab.common.pytest import run
  File "/usr/lib/python2.7/site-packages/logilab/common/pytest.py", line 119, in <module>
    from logilab.common import testlib, STD_BLACKLIST
  File "/usr/lib/python2.7/site-packages/logilab/common/testlib.py", line 63, in <module>
    import unittest2 as unittest
ImportError: No module named unittest2

Expected results:
pytest should not crash but show some useful information

Additional info:
It seems the package is missing dependency on python-unittest2