Got KeyError: u'gebug' when attempted to add Controller and Ironic nodes to cluster

[Kyrylo Romanenko]

Detailed bug description:
Failed to add Controller and Ironic+Controller nodes to cluster.

Steps to reproduce:
1. Deploy cluster:
1 Controller, 1 Compute, 1 Cinder (LVM), 1 Ironic conductor. Neutron VLAN networking.
2. Wait until cluster has deployed.
3. Launch several ironic virtual nodes, run OSTFs etc.
4. Add 1 Controller and 1 Controller+Ironic nodes.
5. Run network verification.
6. Hit "Deploy Changes".

Expected results:
 Add two specified nodes to cluster.
Actual result:
 Got error KeyError: u'gebug'.
Trace from Fuel Master Web backend:
http://paste.openstack.org/show/497072/

Description of the environment:

[root@nailgun ~]# shotgun2 short-report
cat /etc/fuel_build_id:
 353
cat /etc/fuel_build_number:
 353
cat /etc/fuel_release:
 9.0
cat /etc/fuel_openstack_version:
 mitaka-9.0
rpm -qa | egrep 'fuel|astute|network-checker|nailgun|packetary|shotgun':
 fuel-release-9.0.0-1.mos6345.noarch
 fuel-misc-9.0.0-1.mos8340.noarch
 network-checker-9.0.0-1.mos72.x86_64
 fuel-mirror-9.0.0-1.mos135.noarch
 fuel-openstack-metadata-9.0.0-1.mos8679.noarch
 fuel-notify-9.0.0-1.mos8340.noarch
 fuel-ostf-9.0.0-1.mos934.noarch
 fuel-provisioning-scripts-9.0.0-1.mos8679.noarch
 python-fuelclient-9.0.0-1.mos314.noarch
 fuelmenu-9.0.0-1.mos270.noarch
 fuel-9.0.0-1.mos6345.noarch
 fuel-utils-9.0.0-1.mos8340.noarch
 fuel-nailgun-9.0.0-1.mos8679.noarch
 rubygem-astute-9.0.0-1.mos742.noarch
 fuel-library9.0-9.0.0-1.mos8340.noarch
 shotgun-9.0.0-1.mos88.noarch
 fuel-agent-9.0.0-1.mos276.noarch
 fuel-ui-9.0.0-1.mos2681.noarch
 fuel-setup-9.0.0-1.mos6345.noarch
 nailgun-mcagents-9.0.0-1.mos742.noarch
 python-packetary-9.0.0-1.mos135.noarch
 fuel-bootstrap-cli-9.0.0-1.mos276.noarch
 fuel-migrate-9.0.0-1.mos8340.noarch

[Kyrylo Romanenko (kromanenko)]

Diagnostic snapshot: https://drive.google.com/a/mirantis.com/file/d/0B6E70aHvCcRQMlB2SlBQaUFlWG8/view?usp=sharing