Run gate-project-config-pep8 on .py files only
Run gate-project-config-pep8 on .py files only

This patch is to help reduce the check / gate traffic for
project-config.  Over the last 200 commits only 2 or 3 files have been
touched.

Change-Id: I123e07b1fac263292d5d9316bafc7439fc981212
Signed-off-by: Paul Belanger <e7139c8e6c4ea75cc1c287ce081b2dc0f3ab39ec@redhat.com>

openstack-infra/project-config,noorul/os-project-config,openstack-infra/project-config,dongwenjuan/project-config,noorul/os-project-config,Tesora/tesora-project-config,dongwenjuan/project-config,Tesora/tesora-project-config