Snapshot generation hanged on nailgun side but snapshot was actually generated

[Andrey Sledzinskiy]

Steps:
1. Create and deploy any 7.0 cluster
2. Open 'Support' tab and start snapshot generation

Actual result - snapshot was generated in /var/www/nailgun/dump and there are messages about finish in astute.log:
2015-09-02 10:38:03 INFO [668] Casting message to Nailgun: {"method"=>"dump_environment_resp", "args"=>{"task_uuid"=>"1bc9ae2b-c6ad-46bb-a06a-360501ff7f51", "status"=>"ready", "progress"=>100, "msg"=>"2015-09-02 10:35:29 DEBUG 24208 (manager) Initializing snapshot manager\n2015-09-02 10:35:29 DEBUG 24208 (manager)

but it's still generating on UI and nailgun task is 0 progress
{

    "status": "running",
    "name": "dump",
    "cluster": null,
    "result": { },
    "progress": 0,
    "message": null,
    "id": 8,
    "uuid": "1bc9ae2b-c6ad-46bb-a06a-360501ff7f51"

}

{

    "build_id": "263",
    "build_number": "263",
    "release_versions":

{

    "2015.1.0-7.0":

{

    "VERSION":

{

    "build_id": "263",
    "build_number": "263",
    "api": "1.0",
    "fuel-library_sha": "1556601b9b7503285714d7d1e02cc0807b1c68f0",
    "nailgun_sha": "b564ae20116297750bf6402b3a017e219bf4b468",
    "feature_groups":

            [
                "mirantis"
            ],
            "fuel-nailgun-agent_sha": "d7027952870a35db8dc52f185bb1158cdd3d1ebd",
            "openstack_version": "2015.1.0-7.0",
            "fuel-agent_sha": "082a47bf014002e515001be05f99040437281a2d",
            "production": "docker",
            "python-fuelclient_sha": "9643fa07f1290071511066804f962f62fe27b512",
            "astute_sha": "e63709d16bd4c1949bef820ac336c9393c040d25",
            "fuel-ostf_sha": "582a81ccaa1e439a3aec4b8b8f6994735de840f4",
            "release": "7.0",
            "fuelmain_sha": "4dc6799370da4cddf06c04e4ecb7646102298535"
        }
    }

},
"auth_required": true,
"api": "1.0",
"fuel-library_sha": "1556601b9b7503285714d7d1e02cc0807b1c68f0",
"nailgun_sha": "b564ae20116297750bf6402b3a017e219bf4b468",
"feature_groups":

    [
        "mirantis"
    ],
    "fuel-nailgun-agent_sha": "d7027952870a35db8dc52f185bb1158cdd3d1ebd",
    "openstack_version": "2015.1.0-7.0",
    "fuel-agent_sha": "082a47bf014002e515001be05f99040437281a2d",
    "production": "docker",
    "python-fuelclient_sha": "9643fa07f1290071511066804f962f62fe27b512",
    "astute_sha": "e63709d16bd4c1949bef820ac336c9393c040d25",
    "fuel-ostf_sha": "582a81ccaa1e439a3aec4b8b8f6994735de840f4",
    "release": "7.0",
    "fuelmain_sha": "4dc6799370da4cddf06c04e4ecb7646102298535"

}

[Ihor Kalnytskyi (ikalnytskyi)]

We've faced Astute -> RabbitMQ connection problems again. By some reason, astute lost its connection to rabbitmq and message about snapshot completions wasn't delivered to Nailgun's receiver.

[Ihor Kalnytskyi (ikalnytskyi)]

The reason here is the same to reason in reopened bug #1461562