* stable-2.15:
ChangeData#isReviewedBy: Guard against null current patch set
Revert "GetCapabilities#CheckOne: Return json content type"
FormatUtil: Correctly fix the Math#round() error flagged by error-prone
Add a change deleted event/listener
Fix broken link in documentation of receive.requireSignedPush
Change-Id: I57f595d1081f436187df4b73a37a4366cc66196b