Implement rspec function it_raises

On some puppet modules, a it_raises helper is provided. This commit
implements it for puppet-ceilometer.

Change-Id: Ie1c83e09952fed1f114fc07d9944f89e94c413f1
Fail when ssl parameters are missing and rabbit_use_ssl is set to true

This commit causes the run to fail is rabbit_use_ssl parameter is set
to true but the ssl related parameters remains undef.

Change-Id: Idd40601fe4a632204fdde120b857d0e22b6a2aed
Default to utf8 for MySQL

Change default charset to utf8 and default collation order to
utf8_unicode_ci to align with upstream defaults.

Change-Id: I0fb57f14a0d30226c840a6e920f2b3807b90080a
Closes-Bug: #1322715