Update tox.ini to support RHEL 6.x.

In order to support running unit tests on RHEL 6.x we need to patch
eventlet with contrib/redhat-eventlet.patch. We already
have support for this in the tools/install_venv_common.py but we
need to make a couple changes to allow tox to consume this:

1) Sync in the latest intall_venv_common.py from oslo. This changes
 patch to use the -N option (ignore already applied patches) and
 makes it safe to call the patching function more than once.

2) Add a new patch_tox_venv.py script in tools.

3) Update tox.ini to call patch_tox_venv.py before it runs tests and
 coverage.

NOTE: This will hopefully go away eventually once this patch lands:

 https://bitbucket.org/eventlet/eventlet/issue/89/add-a-timeout-argument-to-subprocesspopen#comment-3342969

Change-Id: I3e2b07c3f718e4aede5c5f231ff0cdb7721ec885

contrib/redhat-eventlet.patch

@@ -0,0 +1,16 @@
+--- .nova-venv/lib/python2.6/site-packages/eventlet/green/subprocess.py.orig
+2011-05-25
+23:31:34.597271402 +0000
++++ .nova-venv/lib/python2.6/site-packages/eventlet/green/subprocess.py
+2011-05-25
+23:33:24.055602468 +0000
+@@ -32,7 +32,7 @@
+                     setattr(self, attr, wrapped_pipe)
+         __init__.__doc__ = subprocess_orig.Popen.__init__.__doc__
+
+-    def wait(self, check_interval=0.01):
++    def wait(self, check_interval=0.01, timeout=None):
+         # Instead of a blocking OS call, this version of wait() uses logic
+         # borrowed from the eventlet 0.2 processes.Process.wait() method.
+         try:
+

tools/install_venv_common.py

@@ -185,7 +185,8 @@ class Fedora(Distro):
         self.run_command(['sudo', 'yum', 'install', '-y', pkg], **kwargs)
 
     def apply_patch(self, originalfile, patchfile):
-        self.run_command(['patch', originalfile, patchfile])
+        self.run_command(['patch', '-N', originalfile, patchfile],
+                         check_exit_code=False)
 
     def install_virtualenv(self):
         if self.check_cmd('virtualenv'):

tools/patch_tox_venv.py

@@ -0,0 +1,38 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2013 Red Hat, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import os
+import sys
+
+import install_venv_common as install_venv
+
+
+def main(argv):
+    root = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
+
+    venv = os.environ['VIRTUAL_ENV']
+
+    pip_requires = os.path.join(root, 'tools', 'pip-requires')
+    test_requires = os.path.join(root, 'tools', 'test-requires')
+    py_version = "python%s.%s" % (sys.version_info[0], sys.version_info[1])
+    project = 'Quantum'
+    install = install_venv.InstallVenv(root, venv, pip_requires, test_requires,
+                                       py_version, project)
+    #NOTE(dprince): For Tox we only run post_process (which patches files, etc)
+    install.post_process()
+
+if __name__ == '__main__':
+    main(sys.argv)

tox.ini

@@ -12,7 +12,9 @@ setenv = VIRTUAL_ENV={envdir}
 deps = -r{toxinidir}/tools/pip-requires
        -r{toxinidir}/tools/test-requires
        setuptools_git>=0.4
-commands = nosetests {posargs}
+commands =
+  python tools/patch_tox_venv.py
+  nosetests {posargs}
 
 [tox:jenkins]
 sitepackages = True