Fix validation problems for compute-api

Running "xmllint --noent --noout --schema \
http://docs.rackspace.com/rackbook/wadl.xsd *.wadl", I noticed
a couple of errors that I fixed:
* Wrong URLs for docbook
* Missing declarations

Change-Id: Ia5b47c1010e498d16c4c406f49c0664984a5e123
Merge "Fix validation problems for compute-api"