because it isn't necessarily a filesystem path (and hasn't been for some
time now).  ``Distribution`` objects now have an ``as_requirement()``
method that returns a ``Requirement`` for the distribution's project name
and version.

--HG--
branch : setuptools
extra : convert_revision : svn%3A6015fed2-1504-0410-9fe1-9d1591cc4771/sandbox/trunk/setuptools%4041134