Code change for nova support glance ipv6 address

This code change is for nova can parse glance api servers which is
IPv6 address correctly, also make sure nova commands can be run
successfully in pure ipv6 environment, such as 'nova image-list'
and 'nova boot' command.

Fixes bug 1182830

Change-Id: Ia71002c7038b820db7a63f7d6892e76de4743d8d
Merge "Code change for nova support glance ipv6 address"