[stats] Fuel-stats analytics handler /api/v1/json/oswls returns unicode data

[Andrey Sledzinskiy]

/api/v1/json/oswls returns unicode data like that:
{u'current': [{u'created_at': u'2015-04-11T22:11:42Z', u'minDisk': 0, u'updated_at': u'2015-04-11T22:11:44Z', u'sizeBytes': 13167616, u'minRam': 64, u'id': u'4052ca22-fbeb-47d5-8a5d-0305d6e28370'}], u'removed': [], u'modified': [], u'added': [{u'id': u'4052ca22-fbeb-47d5-8a5d-0305d6e28370', u'time': u'13:17:27.850471'}]}

It would be great it to be 'str' object

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/172977

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/172977
Committed: https://git.openstack.org/cgit/stackforge/fuel-stats/commit/?id=40d2eafc281c84ecf7c3da4bf63af0fea7d50257
Submitter: Jenkins
Branch: master

commit 40d2eafc281c84ecf7c3da4bf63af0fea7d50257
Author: Alexander Kislitsky <email address hidden>
Date: Mon Apr 13 19:00:53 2015 +0300

    Json DB fields export in json exporter fixed

    In previous implementation we should additionaly call json.loads
    on DB json fields for restoring object after export.
    Casting of all DB fields to strings in row_as_dict has been removed.
    Only unserializable fields converted now.
    row_as_dict renamed to row_as_serializable_dict.

    Change-Id: I190391f03068a8f932c6839ae6efb3c2f9fb3afd
    Closes-Bug: #1443448