Upgrade pdxcat/collectd to 1.1.0

The previous version was regularly having problems during installation
where large parts of the module would be lost. This newer version
doesn't seem to suffer from the same problem.

Previous version was 1.0.1

Changelog:
https://github.com/pdxcat/puppet-module-collectd/blob/master/CHANGELOG.md
Merge pull request #250 from alphagov/upgrade-collectd

Upgrade pdxcat/collectd to 1.1.0