[FIXED JENKINS-17402] getItem may return null but may not throw IAE.(cherry picked from commit 7fa8fe4096d0134f598a9d475df1c6199b9b05e7)

Conflicts:
	changelog.html
[JENKINS-17721] Noting.
(cherry picked from commit c10c814b6e403c7588eaf805128f4e549369d06a)

Conflicts:
	changelog.html
[FIXED JENKINS-17724] /about was not showing licenses.
A recent Stapler update caused the Jelly facet to ignore *.xml.
So need to use raw j:include (as plugins were doing), not st:include (as core did).(cherry picked from commit 0bf434845b5de755d730fb73ae1688b02dba8894)

Conflicts:
	changelog.html
	core/src/main/resources/hudson/AboutJenkins/index.jelly
[FIXED JENKINS-17728] ParentBuildAction.parent can sometimes be null.(cherry picked from commit 06e459fffebfe447dcd3edad73559ffb4a8ae707)

Conflicts:
	changelog.html