Bugfix: heat: don't json encode template

Bugfix: heat: don't json encode template

heatclient.common.http.SessionClient
automatically json.dumps the data in kwargs.
If we json dump ourselves we end up double-decoding
which is invalid.

heatclient.common.http.py:

class SessionClient(adapter.LegacyJsonAdapter):
    """HTTP client based on Keystone client session."""

    def request(self, url, method, **kwargs):
        redirect = kwargs.get('redirect')
        kwargs.setdefault('user_agent', USER_AGENT)

        if 'data' in kwargs:
            kwargs['data'] = jsonutils.dumps(kwargs['data'])

kwargs['data'] includes the template,
so this is double-decoding in JSON

JIRA: YARDSTICK-584

Change-Id: I663af42f7e92e285b540b614ceda87f17da5f22d
Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>