Introduce fast8 tox target
Introduce fast8 tox target

The pep8 target has the little known "-HEAD" argument
which makes it only run flake8 on the changes since the
last change in the history.

Even though that's nice, it's sometimes hard to remember
the -HEAD argument. Plus pep8 is running some other
checks on things like the docs.

So if all you want is the pep8 -- -HEAD behavior, this
is a simplied convenient form of it.

Change-Id: I97b277d8ac95ca3ef8379570e0e3886df26263e1

mahak/nova,gooddata/openstack-nova,mahak/nova,klmitch/nova,klmitch/nova,openstack/nova,gooddata/openstack-nova,rahulunair/nova,Juniper/nova,mikalstill/nova,vmturbo/nova,klmitch/nova,Juniper/nova,jianghuaw/nova,vmturbo/nova,jianghuaw/nova,mikalstill/nova,openstack/nova,phenoxim/nova,klmitch/nova,jianghuaw/nova,rajalokan/nova,Juniper/nova,rahulunair/nova,rajalokan/nova,gooddata/openstack-nova,rajalokan/nova,mikalstill/nova,vmturbo/nova,jianghuaw/nova,gooddata/openstack-nova,phenoxim/nova,vmturbo/nova,rajalokan/nova,rahulunair/nova,openstack/nova,mahak/nova,Juniper/nova