Resolve issue when operatingsystemmajrelease fact is not present

* Resolve issue when operatingsystemmajrelease fact is not present due to old version of Facter , issue #5
* Add os_maj_release parameter as way to set the value provided by operatingsystemmajrelease fact
* Use shared examples for unit tests to make reuse of the tests more clean
* Add puppet-syntax to unit tests
* Use lint rake task configuration for introduced puppet-lint 1.0