CLOUDSTACK-2603. EC2RunInstances return xen or ovm as the response value for attribute "hypervisor"
Fix apidocs build

Portable IP section added post portable IP merge

Signed-off-by: Prasanna Santhanam <tsp@apache.org>
Adding docstrings for the portablip test

1. Test to create a portable public ip range
2. Test to acquire a provisioned public ip range

Signed-off-by: Prasanna Santhanam <tsp@apache.org>