Purge unnecessary pip stuff

With the advent of package-based manifests for collectd
and graphite, we no longer need to pre-cache stuff that
was formerly getting installed via pip.  This patch removes
pip-related code from the coi module.

Implements: blueprint die-pip-die
Remove pip logic from base module
Merge pull request #39 from CiscoSystems/bp/die-pip-die

Purge unnecessary pip stuff