Add support for the IPv6 extended attributes in Tempest

Implements blueprint tempest-ipv6-attributes-support

Change-Id: I96bb78828eeb5548bb075f936342a027b9d11652
Fix getting EC2 and S3 urls in create_userrc

Invalid parsing of openstackclient output was introduced in
I03c17cfc9740c3eb257152c95d9c4f021db2c89e. Here command lines
was changed to get urls with no parsing.

Also default EC2_URL was fixed.

Change-Id: Ic46a9989321cf6310c56edeeb737c603a4f9c1ed
Revert "ceilometer.conf configuration option missing os_auth_url"

patch breaks gate (see any logs/screen-ceilometer-acentral.txt.gz
after this patch)

This reverts commit 4c11089739e6d32b77aea0c8fd2dd3d79570b1c8.

Change-Id: I684d50be1b4d580d385a8bb74b3539b1305ec330
Remove *_url inisets since now come from catalog

Another proposed change fetches endpoints from the Keystone catalog as
long as the *_url opts are not present. This change will make Trove on
DevStack use the catalog.

Note: This must merge after https://review.openstack.org/68015.

Change-Id: I397254e72823ab7c7b28014d4fa18e2cefb79e6d
Closes-Bug: #1222891
Merge "Remove *_url inisets since now come from catalog"
Merge "Fix getting EC2 and S3 urls in create_userrc"
Merge "Revert "ceilometer.conf configuration option missing os_auth_url""
Merge "Add support for the IPv6 extended attributes in Tempest"