Graph execute with dry-run option should return task id

[Ekaterina Shutova]

Steps to reproduce:
It would be good to have task id returned when execute deployment:

[root@nailgun ~]# fuel2 graph execute --env 1 --type customgraph --dry-run
Deployment was executed

Now for checking task id we should check task list:
[root@nailgun ~]# fuel2 task list
+----+--------+------------------------------------+---------+--------+----------+
| id | status | name | cluster | result | progress |
+----+--------+------------------------------------+---------+--------+----------+
| 1 | ready | verify_networks | 1 | [] | 100 |
| 2 | ready | check_dhcp | 1 | {} | 100 |
| 3 | ready | check_repo_availability | 1 | {} | 100 |
| 4 | ready | check_repo_availability_with_setup | 1 | {} | 100 |
| 5 | ready | deploy | 1 | {} | 100 |
| 8 | ready | provision | 1 | {} | 100 |
| 9 | ready | deployment | 1 | {} | 100 |
| 10 | ready | dry_run_deployment | 1 | {} | 100 |
+----+--------+------------------------------------+---------+--------+----------+

Expected result:
Have task_id returned after 'fuel2 graph execute'
Actual result:
Only succeed message is returned.

Version:
cat /etc/fuel_build_id:
 467
cat /etc/fuel_build_number:
 467
cat /etc/fuel_release:
 9.0
cat /etc/fuel_openstack_version:
 mitaka-9.0

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/328483

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/328483
Committed: https://git.openstack.org/cgit/openstack/python-fuelclient/commit/?id=2a7e783e1bb8875d1c9c99e355f551499c6aa2fe
Submitter: Jenkins
Branch: master

commit 2a7e783e1bb8875d1c9c99e355f551499c6aa2fe
Author: tivaliy <email address hidden>
Date: Fri Jun 10 23:09:03 2016 +0300

    Add more verbosity to 'fuel2 graph execute' command

    Now the output message for 'fuel2 graph execute' command
    contains task id and enviroment id

    Change-Id: I9e5327a200c6361253ad867f8fe5bd1f6dc2d3ec
    Closes-Bug: 1591187