Updated openstack/openstack
Project: openstack-infra/devstack-gate  6de39b6ebaa03b48e9cc9905c45ff9feb704b61a

Create the stack users ~./cache early

This creates the users ~/.cache directory with proper permissions
prior to running devstack/grenade, avoiding potential permission
issues if a later pip installation is run with sudo but without -H.

Change-Id: I033fd8a28ed593da343315b6fc5a7658ca8c4e31
Related-bug: #1405626