Test with a more recent pip version to avoid a traceback
Test with a more recent pip version to avoid a traceback

```
07:39:05,449 [salt.minion                                :1178][ERROR   ] A command in 'pip.list' had a problem: Traceback (most recent call last):
  File "/tmp/salt-tests-tmpdir/6833-pip-upgrade-pip/bin/pip", line 9, in <module>
    load_entry_point('pip==1.3.1', 'console_scripts', 'pip')()
  File "/tmp/salt-tests-tmpdir/6833-pip-upgrade-pip/lib/python2.6/site-packages/pkg_resources/__init__.py", line 546, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "/tmp/salt-tests-tmpdir/6833-pip-upgrade-pip/lib/python2.6/site-packages/pkg_resources/__init__.py", line 2666, in load_entry_point
    return ep.load()
  File "/tmp/salt-tests-tmpdir/6833-pip-upgrade-pip/lib/python2.6/site-packages/pkg_resources/__init__.py", line 2339, in load
    return self.resolve()
  File "/tmp/salt-tests-tmpdir/6833-pip-upgrade-pip/lib/python2.6/site-packages/pkg_resources/__init__.py", line 2345, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "/tmp/salt-tests-tmpdir/6833-pip-upgrade-pip/lib/python2.6/site-packages/pip/__init__.py", line 13, in <module>
    from pip.commands import commands, get_similar_commands, get_summaries
  File "/tmp/salt-tests-tmpdir/6833-pip-upgrade-pip/lib/python2.6/site-packages/pip/commands/__init__.py", line 6, in <module>
    from pip.commands.bundle import BundleCommand
  File "/tmp/salt-tests-tmpdir/6833-pip-upgrade-pip/lib/python2.6/site-packages/pip/commands/bundle.py", line 5, in <module>
    from pip.commands.install import InstallCommand
  File "/tmp/salt-tests-tmpdir/6833-pip-upgrade-pip/lib/python2.6/site-packages/pip/commands/install.py", line 5, in <module>
    from pip.req import InstallRequirement, RequirementSet, parse_requirements
  File "/tmp/salt-tests-tmpdir/6833-pip-upgrade-pip/lib/python2.6/site-packages/pip/req/__init__.py", line 3, in <module>
    from .req_install import InstallRequirement
  File "/tmp/salt-tests-tmpdir/6833-pip-upgrade-pip/lib/python2.6/site-packages/pip/req/req_install.py", line 20, in <module>
    import pip.wheel
  File "/tmp/salt-tests-tmpdir/6833-pip-upgrade-pip/lib/python2.6/site-packages/pip/wheel.py", line 23, in <module>
    from pip.exceptions import InvalidWheelFilename, UnsupportedWheel
ImportError: cannot import name InvalidWheelFilename
```

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt