fixes [JENKINS-11374] - Add deletion option on "list of Shelved Projects
Fix to persist Shelve project property whenever the job is updated
this fix would resolve JENKINS-10544
renamed test case
Update ItemListenerImplTest to use JenkinsRule.
Port remaining tests to use JenkinsRule.
fixes [JENKINS-11374] - Add deletion option on "list of Shelved Projects
Merge pull request #4 from christiangalsterer/master

[JENKINS-11374] - Add deletion option on 'list of Shelved Projects'