Add doc support for Fixed IPs extension

Modified:  api-ref/src/docbkx/api-ref.xml >> to render new section
Added the fixed-ips.wadl file and two more samples for the unreserve action in api_samples
Renamed and modified previous samples to add some details.
Fixes: bug 1077557

Change-Id: Iefcbcf7963e8c38a37d7bfba353b8be7a8d0fd19
Merge "Add doc support for Fixed IPs extension"