[cli] In case of errors show not only exception message and but also response from nailgun

[Evgeniy L]

Step to reproduce:

1. create cluster
2. tried to add node

Actual result:
Got an exception
(nailgun)[root@fuel fuelclient]# fuel node set --env 2 --node 1 --role controller
HTTP Error 400: Bad Request

Expected result:
Exception with error message where I can see description of problem (just show response from nailgun in case of such errors)
Example:

(nailgun)[root@fuel fuelclient]# fuel node set --env 2 --node 1 --role controller
HTTP Error 400: Bad Request

(nailgun)[root@fuel fuelclient]# fuel node set --env 2 --node 1 --role controller --debug
GET http://127.0.0.1:8000/api/v1/clusters/2/
PUT http://127.0.0.1:8000/api/v1/nodes/ data=[{"pending_addition": true, "pending_roles": ["controller"], "cluster_id": "2", "id": 1, "pending_deletion": false}]
HTTP Error 400: Bad Request

(nailgun)[root@fuel fuelclient]# curl -X PUT --data '[{"pending_addition": true, "pending_roles": ["controller"], "cluster_id": "2", "id": 1, "pending_deletion": false}]' http://127.0.0.1:8000/api/v1/nodes/
[127.0.0.1] Invalid ID specified(nailgun)[root@fuel fuelclient]#

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/61758

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/61758
Committed: https://git.openstack.org/cgit/stackforge/fuel-web/commit/?id=b267a319b26949ee26c3c018e9ef6ce021c43a84
Submitter: Jenkins
Branch: master

commit b267a319b26949ee26c3c018e9ef6ce021c43a84
Author: Alexandr Notchenko <email address hidden>
Date: Thu Dec 12 18:36:05 2013 +0400

    api call error forwarding to cli

    * prints api call error along with http error
    * checks for empty error response body

    Closes-bug: #1259585

    Change-Id: I332fa960d74681610e6cf6b759c9b6bd5f91ec91