Fix status code of server's action confirm_resize for v3

The status code of confirm_resize should be 202, but it
returns 204 now. That because it returns HTTPNoContent
that overwrites the status code of decorator 'wsgi.response(202)'

And adds API samples for confirm_resize that used to test
the status code of confirm_resize.

Partially implements blueprint v3-api-unittests
Closes-bug: #1233561

Change-Id: I50a3046866af0a1efdb5c41ded40f973b02843e8
Uses oslo.imageutils

Commit 035668 had the QemuImgInfo class moved to Oslo.
This class was copied from Nova to Cinder and diverged since then.
The two projects will be able to use identical classes by importing imageutils.

Change-Id: If1962680906b3736d3f16f306b077483b122f878
Validate parameters of agent API

The agent API has some parameters, but they are not validated.
Each parameter is stored to the table "agent_builds", and each column
is defined as varchar(255).

mysql> desc agent_builds;
+--------------+--------------+------+-----+---------+----------------+
| Field        | Type         | Null | Key | Default | Extra          |
+--------------+--------------+------+-----+---------+----------------+
| created_at   | datetime     | YES  |     | NULL    |                |
| updated_at   | datetime     | YES  |     | NULL    |                |
| deleted_at   | datetime     | YES  |     | NULL    |                |
| id           | int(11)      | NO   | PRI | NULL    | auto_increment |
| hypervisor   | varchar(255) | YES  | MUL | NULL    |                |
| os           | varchar(255) | YES  |     | NULL    |                |
| architecture | varchar(255) | YES  |     | NULL    |                |
| version      | varchar(255) | YES  |     | NULL    |                |
| url          | varchar(255) | YES  |     | NULL    |                |
| md5hash      | varchar(255) | YES  |     | NULL    |                |
| deleted      | int(11)      | YES  |     | NULL    |                |
+--------------+--------------+------+-----+---------+----------------+

This patch adds the validation with the type and the length.

Closes-Bug: 1240458

Change-Id: Id06235ebde62f7b96c55b0bd2be5d941bfd2e999
Expose additional status in baremetal API extension

Add fields: uuid, task_state, updated_at, and pxe_config_path
to aid system admins in troubleshooting issues.

Fixes bug 1184449

Change-Id: Ia4c03cb228b3efe602455bf05883ddf03b7f18da
Merge "Fix status code of server's action confirm_resize for v3"
Merge "Uses oslo.imageutils"
Merge "Validate parameters of agent API"
Merge "Expose additional status in baremetal API extension"