setup/installation-test/swc-installation-test-2.py: Prefer pip to easy_install

setup/installation-test/swc-installation-test-2.py: Prefer pip to easy_install

For virtual-pypi-installer.  easy_install is part of Setuptools [1],
which was dead for several years.  The Distribute fork took over, but
has since been merged back into a revitalized Setuptools (since
Setuptools v0.7 [2], tagged on 2013-06-02 [3]).  Pip >= v1.4 actually
requires a modern Setuptools, not Distribute [4].  Pip also improves
on easy_install [5], which does not currently support uninstalling
packages [6].

[1]: http://pythonhosted.org/setuptools/
[2]: http://pythonhosted.org/distribute/
[3]: https://bitbucket.org/pypa/setuptools/commits/tag/0.7
[4]: http://www.pip-installer.org/en/latest/installing.html#id6
[5]: http://www.pip-installer.org/en/latest/other-tools.html#easy-install
[6]: http://pythonhosted.org/setuptools/easy_install.html#uninstalling-packages