Install python meta-package
Install python meta-package

The Makefile for docs calls 'python' so the python executable needs to
be available to build docs.

seankelly/buildbot-infra,djmitche/buildbot-infra,djmitche/buildbot-infra,buildbot/buildbot-infra,djmitche/buildbot-infra,buildbot/buildbot-infra,seankelly/buildbot-infra,seankelly/buildbot-infra,buildbot/buildbot-infra