Pin puppet-sensu module
Pin puppet-sensu module

Newest versions of puppet-sensu don't take into account the
serverless usage we can have with puppet ("puppet apply" vs "puppet
client"), making CI fail the unit tests for this module.

An upstream bug has been open:
https://github.com/sensu/sensu-puppet/issues/1098

The hash we're pinning is the same as in
https://github.com/redhat-openstack/rdoinfo/blob/master/tags/stein-uc.yml#L880

Change-Id: I1784a06052909b108c862ef76fc69e57bd778987
Closes-Bug: #1821591

openstack/puppet-tripleo,openstack/puppet-tripleo,openstack/puppet-tripleo