Fix duplicated hypervisor config sec, rstrctre

This patch fixes the current situation where we have two sections
regarding configuring hypervisors in compute admin guide. The section
also erroneously stated that its information was useless unless you
had a running install - fixed!

This also makes the breakdown between the default (kvm) and other
hypervisors a bit better.

fixes bug 1026674

Change-Id: I3c366913d8f5bd8ebf9779e623001b4449a10453
Merge "Fix duplicated hypervisor config sec, rstrctre"