[google|dns] Add the ability to wait for a change completion RRSet operations

- Enable syncronous calls on create, modify and destroy RRSets (asyncronous by default)
[google|dns] Add get method to RRSet

- Add "get" method and tests to Resource Record Sets
Fix floating_ip detection for OpenStack Folsom Release

OS-EXT-IPS:type was introduced only in Grizzly, thus Folsom
cannot rely on this api extension.
See https://bugs.launchpad.net/openstack-api-site/+bug/1128562
Meanwhile we can designate floating ip from fixed_ip by provided
fallback
Added ELB tags methods, mocks, and tests

Thanks to 20goto10 Ben Chadwick <bchadwick@mdsol.com> for the initial groundwork
Merge pull request #3209 from frodenas/gce_dns

[google|dns] Improve Resource Record Sets changes
Rackspace neutron (networking) support
Remove duplicated hash key in rackspace/mock_data.rb
Merge pull request #3222 from deepj/master

Remove duplicated hash key in rackspace/mock_data.rb
Merge pull request #3218 from ericsakowski/feature_elb_tags

Added ELB tags methods, mocks, and tests
Merge pull request #3220 from mdarby/neutron

Rackspace neutron (networking) support
Merge pull request #3211 from ytsarev/folsom_floating_ip

Fix floating_ip detection for OpenStack Folsom Release