Fix test "set_duplicate_hostname"

[Sergey Novikov]

Test "set_duplicate_hostname" https://github.com/openstack/fuel-qa/blob/78ae58811d042156f968d88eb42ea43c79b849ab/fuelweb_test/tests/test_custom_hostname.py#L219 fails with AssertionError https://github.com/rackerlabs/python-proboscis/blob/master/proboscis/asserts.py#L183.

Seems, the reason of this failure is nailgun allows to set duplicate hostname for node, but actually nailgun raises exception (I verified it manually).

After the recovering of failed env I observed that custom hostname was applied for only one node, other nodes had hostnames by default. Any messages about duplicated hostname and code 409 were not found in /var/log/nailgun/app.log. So, it seems like that second request with duplicated hostname was not sent. Anyway, we need to research this issue deeply

failed job: https://product-ci.infra.mirantis.net/job/9.x.system_test.ubuntu.custom_hostname/29/console

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/368848

[Sergey Novikov (snovikov)]

After investigation of this problem the strange thing was found. Sometimes method "self.fuel_web.client.list_nodes()" returns lists of nodes which were sorted by different, and as consequence of that, sometimes self.fuel_web.client.list_nodes()[0] equals self.fuel_web.client.list_nodes()[1]. So, we need to exclude this behavior from our test

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/368848
Committed: https://git.openstack.org/cgit/openstack/fuel-qa/commit/?id=f77235fed4f9bdfb3a2d4db7555c408777d3ef7c
Submitter: Jenkins
Branch: master

commit f77235fed4f9bdfb3a2d4db7555c408777d3ef7c
Author: Alisa Tselovalnikova <email address hidden>
Date: Mon Sep 12 16:30:30 2016 +0300

    Exclude applying of hostname for same node a twice

    Sometimes method "self.fuel_web.client.list_nodes()" returns lists
    of nodes which were sorted by differently, and as consequence of that,
    sometimes self.fuel_web.client.list_nodes()[0] equals
    self.fuel_web.client.list_nodes()[1].

    Change-Id: I0e1e32c11bb759b882ef2c548f50e4d81aa85b46
    Closes-Bug: #1613846

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/mitaka
Review: https://review.openstack.org/370759

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/370759
Committed: https://git.openstack.org/cgit/openstack/fuel-qa/commit/?id=4ae0a608edf8e79dd824e1327193636f540c3b77
Submitter: Jenkins
Branch: stable/mitaka

commit 4ae0a608edf8e79dd824e1327193636f540c3b77
Author: Alisa Tselovalnikova <email address hidden>
Date: Mon Sep 12 16:30:30 2016 +0300

    Exclude applying of hostname for same node a twice

    Sometimes method "self.fuel_web.client.list_nodes()" returns lists
    of nodes which were sorted by differently, and as consequence of that,
    sometimes self.fuel_web.client.list_nodes()[0] equals
    self.fuel_web.client.list_nodes()[1].

    Change-Id: I0e1e32c11bb759b882ef2c548f50e4d81aa85b46
    Closes-Bug: #1613846
    (cherry picked from commit f77235fed4f9bdfb3a2d4db7555c408777d3ef7c)