[install] Fix the broken link for compute overview
[install] Fix the broken link for compute overview

Fix a broken link for config-ref guide in the install-guide

Closes-Bug: #1692411
Change-Id: I619578b4ec4bd8e9d4a4a3fffb9428be538eed25

openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals