restore Heat stack failure logs for CI

restore Heat stack failure logs for CI

We need to see what Heat failures occured
so that we can debug CI failures.

The only way to do this seems to be to use the
private event_utils.get_events function to
query for all failures

Also since we had a failure go ahead and dump the
Heat template that failed.

Sample output:

2018-03-25 23:50:08,765 [INFO] yardstick.orchestrator.heat heat.py:629 Creating stack 'yardstick-460ed969' START
2018-03-25 23:50:21,932 [ERROR] yardstick.orchestrator.heat heat.py:644 Resource CREATE failed: BadRequest: resources.yardstick-460ed969-xe1: Invalid input for operation: physical_network 'nosuch' unknown for flat provider network.
Neutron server returns request_ids: ['req-6f981f1e-a9e2-4114-af84-1ee528aed51b']
2018-03-25 23:50:21,933 [ERROR] yardstick.orchestrator.heat heat.py:644 BadRequest: resources.yardstick-460ed969-xe1: Invalid input for operation: physical_network 'nosuch' unknown for flat provider network.
Neutron server returns request_ids: ['req-6f981f1e-a9e2-4114-af84-1ee528aed51b']
2018-03-25 23:50:21,972 [ERROR] yardstick.orchestrator.heat heat.py:645 {'description': '\n'
                'All referred generated resources are prefixed with the '
                'template\n'
                'name (i.e. yardstick-460ed969).\n',
 'heat_template_version': '2013-05-23',
 'outputs': {'trafficgen_1.yardstick-460ed969': {'description': 'VM UUID',
                                                 'value': {'get_resource': 'trafficgen_1.yardstick-460ed969'}},
             'trafficgen_1.yardstick-460ed969-fip': {'description': 'floating '
                                                                    'ip '
JIRA: YARDSTICK-998

Change-Id: Ia8f4e5ba7e280fb9086519680d5ee90a2b442e6b
Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>