Add pip installer to the python cartridge

Add pip installer to the python cartridge and use it when creating
python 3.3 venvs.

This fixes bug 1098877.
Merge pull request #5465 from ncdc/python-3.3-pip

Add pip installer to the python cartridge
Automatic commit of package [openshift-origin-cartridge-jenkins-client] release [1.21.2-1].
Automatic commit of package [rubygem-openshift-origin-node] release [1.25.6-1].
Automatic commit of package [openshift-origin-cartridge-jbosseap] release [2.18.3-1].
Automatic commit of package [openshift-origin-cartridge-jbossews] release [1.24.3-1].
Automatic commit of package [openshift-origin-cartridge-postgresql] release [1.25.3-1].
Automatic commit of package [openshift-origin-cartridge-jenkins] release [1.22.3-1].
Automatic commit of package [rubygem-openshift-origin-routing-activemq] release [0.4.2-1].
Automatic commit of package [rubygem-openshift-origin-container-selinux] release [0.8.2-1].
Automatic commit of package [openshift-origin-cartridge-php] release [1.25.3-1].
Automatic commit of package [openshift-origin-cartridge-python] release [1.25.3-1].
Automatic commit of package [rubygem-openshift-origin-controller] release [1.25.4-1].
Automatic commit of package [rubygem-openshift-origin-frontend-apache-vhost] release [0.7.2-1].
Automatic commit of package [rubygem-openshift-origin-console] release [1.25.4-1].
Automatic commit of package [openshift-origin-cartridge-jbossas] release [1.25.3-1].
Automatic commit of package [openshift-origin-cartridge-diy] release [1.23.3-1].
Automatic commit of package [openshift-origin-cartridge-ruby] release [1.25.4-1].
Automatic commit of package [openshift-origin-cartridge-perl] release [1.24.3-1].
Automatic commit of package [openshift-origin-cartridge-nodejs] release [1.26.3-1].