Updated openstack/openstack
Project: openstack-dev/devstack  6db41b9716c5a82a32818d87ad3af662ecc1382a

Exact match rhel6

With rhel6 & rhel7 having a common prefix, use an exact match to make
sure we don't mix them up.  This is breaking Centos7.

Change-Id: Ia4665ea78f0bafeaa2b2284a6d3de4474ea195e9