[Distutils] easy_install not working

[Andrea Crotti]

Since some days easy_install doesn't work correctly anymore.
I get for example something similar.
Any idea of what it could be?
In general setuptools is working perfectly, only easy_install is not 
working anymore..

[andrea at precision ~]$ easy_install-2.7 --user python-graph-core
Traceback (most recent call last):
   File "/home/andrea/.local/bin/easy_install-2.7", line 5, in <module>
     from pkg_resources import load_entry_point
   File "/usr/lib/python2.7/site-packages/pkg_resources.py", line 2711, 
in <module>
     parse_requirements(__requires__), Environment()
   File "/usr/lib/python2.7/site-packages/pkg_resources.py", line 584, 
in resolve
     raise DistributionNotFound(req)
pkg_resources.DistributionNotFound: distribute==0.6.21