vlan_splinters data has staled state after disabling on ui

[Artem Roma]

"build_id": "2014-04-16_01-00-26",
"mirantis": "yes",
"build_number": "105",
"nailgun_sha": "c7e847a90386a17efc7ba46ba6a25f1c99e2d354",
"production": "dev",
"ostf_sha": "1ac04769cc8034438ccf1176860b25d0f5601c4a",
"fuelmain_sha": "fd3abbd6068e8317fd6761d3bfd74552b56b58cb",
"astute_sha": "0cb0b26773bd269000a14748e8ba49419462ecaf",
"release": "5.0",
"fuellib_sha": "cf93865f4b6056c4d6426b2d0645e160c32a8c42"

Step to reproduce:
1. Create cluster with default parameters.
2. Go to "Settings" tab, check "Vlan Splinters" sections and chose one of available variants, save changes.
3. Inspect Nailgun api log: PUT request data on url /api/clusters/<cluster_id>/attributes in section "vlan_splinters" contains corresponding to chosen on ui value in key "value".
4. Go to "Settings" tab again and uncheck combo box in "Vlan Splinters" section, save changes.
5. Inspect Nailgun api log: data for new PUT request is the same as for previous one with "Vlan Splinters" enabled, should have changed to "disabled".

[Artem Roma (aroma-x)]

Fix for this issue https://review.openstack.org/#/c/89543/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/89543
Committed: https://git.openstack.org/cgit/stackforge/fuel-web/commit/?id=b27862ba7d0576e88069da12bcf7e6b44b1dcf14
Submitter: Jenkins
Branch: master

commit b27862ba7d0576e88069da12bcf7e6b44b1dcf14
Author: Artem Roma <email address hidden>
Date: Tue Apr 22 14:36:32 2014 +0300

    Proper vlan_splinters data processing added

    Processing of disabling/enabling logic for "vlan_splinters" on backend
    added.

    Change-Id: I7dd9b9e9cd2fa974b63ccb86f9cb72393ddab175
    Closes-Bug: #1308492