Convert aggregates testing to use httpretty

This is the first in the series and so contains some setup classes. In
general the original data will not be able to be removed from fakes
until the very end because testing shell depends on a lot of it.

Change-Id: I499fe968923b9452f60c1b2ca50d5749e89827de
blueprint: httpretty-testing
Print message if instance is successfully deleted v3

Also change the message for v1_1.

Change-Id: I35eaf1a7670de79e3b75acaffe7ae13018b0a762
Closes-bug: 1312087
Some Help Messages Missing Translation Support

v1_1/contrib/baremetal is missing translation support for some help
messages. Fix this.

Change-Id: Iea354fef1c7f41361b66ed4e143b3f1f5e562d88
Merge "Convert aggregates testing to use httpretty"
Merge "Print message if instance is successfully deleted v3"