remove quick-fix comment for the solution to issue #169.

Although the original problematic use case when we are replacing a zipped egg
distribution with another zipped egg distribution is now cleanly handled by
fixing all existing zipimport.zipimporter loaders, this fix is still valid for
cases when replacing a distribution with a non-zipped egg folder.

--HG--
extra : source : efd6a8b82bafdbcfad1971b7e0f470e19191be1a

setuptools/command/easy_install.py

@@ -646,13 +646,6 @@ Please make the appropriate changes for your system and try again.
     def process_distribution(self, requirement, dist, deps=True, *info):
         self.update_pth(dist)
         self.package_index.add(dist)
-        # First remove the dist from self.local_index, to avoid problems using
-        # old cached data in case its underlying file has been replaced.
-        #
-        # This is a quick-fix for a zipimporter caching issue in case the dist
-        # has been implemented as and already loaded from a zip file that got
-        # replaced later on. For more detailed information see setuptools issue
-        # #168 at 'http://bitbucket.org/pypa/setuptools/issue/168'.
         if dist in self.local_index[dist.key]:
             self.local_index.remove(dist)
         self.local_index.add(dist)