xci: playbooks: Fix message on fail task for deployed scenario

xci: playbooks: Fix message on fail task for deployed scenario

The fail message was a bit weird since it listed all the scenarion
information as below:

TASK [Fail if {'scm': u'git', 'src':
u'https://git.opnfv.org/releng-xci', 'scenario': u'os-nosdn-nofeature',
'installers': [{'flavors': [u'ha', u'mini', u'noha'], 'installer':
u'osa', 'distros': [u'opensuse', u'ubuntu', u'centos']}], 'version': u'master', 'role':
u'xci/scenarios/os-nosdn-nofeature/role/os-nosdn-nofeature'} is not
supported] ***
skipping: [localhost]

This looks awkward and we should only list the actual scenario name
instead.

Change-Id: I725793f91661f00606573906847336716fecd418
Signed-off-by: Markos Chandras <mchandras@suse.de>