ci: ensure latest pip is installed
ci: ensure latest pip is installed

It seems like recent cryptography version requires the latest
pip.

Change-Id: I2aa5ab7d182c36f4c092f1a78fa9eac57e09278f

openstack-packages/delorean,openstack-packages/delorean,openstack-packages/DLRN,openstack-packages/DLRN