Make tox work on EL7

Without it, it fail because it try to use --download-cache
option with pip, and pip fail. There is no workaround as
far as I know, and this is currently causing trouble, see
https://jenkins-fedora-apps.apps.ci.centos.org/blue/organizations/jenkins/fedbadges/detail/PR-75/10/pipeline#log-170

python-tox.spec

@@ -7,7 +7,7 @@
 %global pypiname tox
 Name:           python-tox
 Version:        1.4.2
-Release:        8%{?dist}
+Release:        9%{?dist}
 Summary:        Virtualenv-based automation of test activities
 
 # file toxbootstrap.py is licensed under MIT License
@@ -15,6 +15,8 @@ License:        GPLv2+ and MIT
 URL:            http://codespeak.net/tox
 Source0:        http://pypi.python.org/packages/source/t/%{pypiname}/%{pypiname}-%{version}.zip
 #md5=dc52acf22eb57eaa33e704f8a54e7b34
+# variation of https://github.com/tox-dev/tox/commit/ac1b57ac659f41cf157d6d847b57ba82f8987137
+Patch0:         tox-1.4.2-fix_epel7.diff
 
 BuildArch:      noarch
 BuildRequires:  python2-devel
@@ -41,6 +43,7 @@ can use for:
 
 %prep 
 %setup -q -n %{pypiname}-%{version}
+%patch0 -p1
 
 %build
 %{__python} setup.py build
@@ -74,6 +77,9 @@ TOXENV=py27 %{__python} setup.py test
 
 
 %changelog
+* Thu Apr 02 2020 Michael Scherer <misc@zarb.org> - 1.4.2-9
+- fix run on newer pip on EL7
+
 * Thu Feb 14 2013 Fedora Release Engineering <rel-eng@lists.fedoraproject.org> - 1.4.2-8
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_19_Mass_Rebuild
 

tox-1.4.2-fix_epel7.diff

@@ -0,0 +1,15 @@
+Index: tox/_venv.py
+===================================================================
+--- tox-1.4.2/tox/_venv.py
++++ tox-1.4.2.orig/tox/_venv.py	2020-04-02 16:05:49.006344130 +0200
+@@ -224,10 +224,6 @@
+ 
+     def pip_install(self, args, indexserver=None, action=None):
+         argv = ["pip", "install"] + self._commoninstallopts(indexserver)
+-        if self.envconfig.downloadcache:
+-            self.envconfig.downloadcache.ensure(dir=1)
+-            argv.append("--download-cache=%s" %
+-                self.envconfig.downloadcache)
+         for x in ('PIP_RESPECT_VIRTUALENV', 'PIP_REQUIRE_VIRTUALENV'):
+             try:
+                 del os.environ[x]