Comment 12 for bug 1446089

Env:

{
  "build_id": "2015-05-12_08-34-41",
  "build_number": "406",
  "release_versions": {
    "2014.2-6.0": {
      "VERSION": {
        "build_id": "2014-12-26_14-25-46",
        "ostf_sha": "a9afb68710d809570460c29d6c3293219d3624d4",
        "build_number": "58",
        "api": "1.0",
        "nailgun_sha": "5f91157daa6798ff522ca9f6d34e7e135f150a90",
        "production": "docker",
        "fuelmain_sha": "81d38d6f2903b5a8b4bee79ca45a54b76c1361b8",
        "astute_sha": "16b252d93be6aaa73030b8100cf8c5ca6a970a91",
        "feature_groups": [
          "mirantis"
        ],
        "release": "6.0",
        "fuellib_sha": "fde8ba5e11a1acaf819d402c645c731af450aff0"
      }
    },
    "2014.2.2-6.1": {
      "VERSION": {
        "build_id": "2015-05-12_08-34-41",
        "build_number": "406",
        "api": "1.0",
        "fuel-library_sha": "156fb11bbf3e12e7c73a9a3ac785c9d33d4ac343",
        "nailgun_sha": "0d077692e813720410c52bc720a8462725446e0d",
        "feature_groups": [
          "mirantis"
        ],
        "openstack_version": "2014.2.2-6.1",
        "production": "docker",
        "python-fuelclient_sha": "af6c9c3799b9ec107bcdc6dbf035cafc034526ce",
        "astute_sha": "e319b19158fc416d911edf0c06667e810c457b02",
        "fuel-ostf_sha": "51b41cba7572aefa4a98e40fdecdbc05efb2e1ea",
        "release": "6.1",
        "fuelmain_sha": "51b86bb24b27742a22b23e2ae3dfc850c47e5fbf"
      }
    }
  },
  "auth_required": true,
  "api": "1.0",
  "fuel-library_sha": "156fb11bbf3e12e7c73a9a3ac785c9d33d4ac343",
  "nailgun_sha": "0d077692e813720410c52bc720a8462725446e0d",
  "feature_groups": [
    "mirantis"
  ],
  "openstack_version": "2014.2.2-6.1",
  "production": "docker",
  "python-fuelclient_sha": "af6c9c3799b9ec107bcdc6dbf035cafc034526ce",
  "astute_sha": "e319b19158fc416d911edf0c06667e810c457b02",
  "fuel-ostf_sha": "51b41cba7572aefa4a98e40fdecdbc05efb2e1ea",
  "release": "6.1",
  "fuelmain_sha": "51b86bb24b27742a22b23e2ae3dfc850c47e5fbf"
}

Steps:
1. Create and deploy next 6.0-58 cluster - CentOS, simple, Neutron Vlan, Ceph for volumes and images, 1 controller+ceph, 2 compute+ceph
2. Upgrade fuel to 6.1
3. Do: http://paste.mirantis.net/show/381/
4. Delete 1 compute+ceph node from 6.0 cluster and start re-deployment

Actual:

2015-05-12T18:54:58 err: [651] Error running RPC method remove_nodes: undefined method `[]' for nil:NilClass, trace:
["/usr/lib64/ruby/gems/2.1.0/gems/astute-6.1.0/lib/astute/pre_delete.rb:74:in `remove_ceph_mons'",
 "/usr/lib64/ruby/gems/2.1.0/gems/astute-6.1.0/lib/astute/orchestrator.rb:202:in `remove_ceph_mons'",
 "/usr/lib64/ruby/gems/2.1.0/gems/astute-6.1.0/lib/astute/orchestrator.rb:210:in `perform_pre_deletion_tasks'",
 "/usr/lib64/ruby/gems/2.1.0/gems/astute-6.1.0/lib/astute/orchestrator.rb:103:in `remove_nodes'",
 "/usr/lib64/ruby/gems/2.1.0/gems/astute-6.1.0/lib/astute/server/dispatcher.rb:168:in `remove_nodes'",
 "/usr/lib64/ruby/gems/2.1.0/gems/astute-6.1.0/lib/astute/server/server.rb:142:in `dispatch_message'",
 "/usr/lib64/ruby/gems/2.1.0/gems/astute-6.1.0/lib/astute/server/server.rb:103:in `block in dispatch'",
 "/usr/lib64/ruby/gems/2.1.0/gems/astute-6.1.0/lib/astute/server/task_queue.rb:64:in `call'",
 "/usr/lib64/ruby/gems/2.1.0/gems/astute-6.1.0/lib/astute/server/task_queue.rb:64:in `block in each'",
 "/usr/lib64/ruby/gems/2.1.0/gems/astute-6.1.0/lib/astute/server/task_queue.rb:56:in `each'",
 "/usr/lib64/ruby/gems/2.1.0/gems/astute-6.1.0/lib/astute/server/task_queue.rb:56:in `each'",
 "/usr/lib64/ruby/gems/2.1.0/gems/astute-6.1.0/lib/astute/server/server.rb:101:in `each_with_index'",
 "/usr/lib64/ruby/gems/2.1.0/gems/astute-6.1.0/lib/astute/server/server.rb:101:in `dispatch'",
 "/usr/lib64/ruby/gems/2.1.0/gems/astute-6.1.0/lib/astute/server/server.rb:85:in `block in perform_main_job'"]