[admin-guide] Minor refactoring of the PCI guide
[admin-guide] Minor refactoring of the PCI guide

Clarify some wording and fix some text wrapping.

Change-Id: I5d42d5bfc38037f6de7f31951da685b54da5a6bb

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