Change help message for volume-update

`nova volume-update <server> <volume> <volume>` to
`nova volume-update <server> <attachment> <volume>`

Change-Id: Ie820843c3e8d23659075c1d6b4fdd47f639b3b58
Closes-bug: 1326613
Convert Floating IP tests to httpretty

Change-Id: I0f6816868580af32ee93c0bfdf2c113c6c6ecd13
blueprint: httpretty-testing
Convert Floating IPs DNS tests to httpretty

Change-Id: I19dfadbe9103145a6b80d8ce10d2b6d3ce326ffa
blueprint: httpretty-testing
Remove _print_volume from volume-update

Since the response of volume-update do not contain a body, just a status
code 202, so when calling _print_volume(volume), there will be an error:
`ERROR (AttributeError): 'NoneType' object has no attribute '_info'`.

Change-Id: I950ae7dca5e847beae7295d72d009f2d07d07c51
Closes-bug: 1321205
add tox target for python 3.4

Ubuntu 14.04 has python 3.4 so add a 3.4 target. 
Note that this will fail unless
you have new enough virtualenv. Recommend you install the packaged
version of 1.11.4 and get rid of any pip installed ones.

Change-Id: Ib54dc49fca2463f1c5cd788b48d06bd85be52655
Merge "Remove _print_volume from volume-update"
Merge "Change help message for volume-update"
Merge "Convert Floating IP tests to httpretty"
Merge "Convert Floating IPs DNS tests to httpretty"
Merge "add tox target for python 3.4"