fixup! easy_install: add slapos.libnetworkcache support

This fixes filtering of distributions, like py_version for EGG_DIST.

See commit fb785cb3.

src/zc/buildout/easy_install.py

@@ -485,9 +485,14 @@ class Installer:
                             with nc:
                                 for entry in nc.select(key):
                                     basename = entry['basename']
-                                    dist = next(iter(distros_for_location(
-                                        entry['sha512'], basename)))
-                                    if filter_precedence(dist):
+                                    for dist in distros_for_location(
+                                            entry['sha512'], basename):
+                                        # The version comparison is to keep
+                                        # the one that's correctly parsed by
+                                        # distros_for_location.
+                                        if (dist.version == version and
+                                                self._env.can_add(dist) and
+                                                filter_precedence(dist)):
                                             dist.networkcache = (
                                                 basename, requirement, source)
                                             dists.append(dist)