[9.1] [contrail] mos-release wasn't found

[vnaumov]

Detailed bug description:
  Fuel installation has failed because of "mos-release wasn't found"

Steps to reproduce:
  Try to prepare Fuel master node with fuel-qa

Expected results:
  Master is prepared

Actual result:
File "/home/jenkins/workspace/9.1.contrail.5.0.0.bvt.test.juniper/plugin_test/fuel-qa/fuelweb_test/helpers/decorators.py", line 120, in wrapper
    result = func(*args, **kwargs)
  File "/home/jenkins/workspace/9.1.contrail.5.0.0.bvt.test.juniper/plugin_test/fuel-qa/fuelweb_test/tests/base_test_case.py", line 367, in setup_master
    self.fuel_post_install_actions()
  File "/home/jenkins/workspace/9.1.contrail.5.0.0.bvt.test.juniper/plugin_test/fuel-qa/fuelweb_test/tests/base_test_case.py", line 233, in fuel_post_install_actions
    self.env.admin_actions.prepare_admin_node_for_mos_mu()
  File "/home/jenkins/workspace/9.1.contrail.5.0.0.bvt.test.juniper/plugin_test/fuel-qa/fuelweb_test/helpers/fuel_actions.py", line 337, in prepare_admin_node_for_mos_mu
    "mos-release wasn't found")
  File "/home/jenkins/90-venv/local/lib/python2.7/site-packages/proboscis/asserts.py", line 163, in assert_true
    raise ASSERTION_ERROR(message)
AssertionError: mos-release wasn't found

[vnaumov (vnaumov-b)]

have been fixed