The subject method name should match the field name.
Plus, there is no clear "creation date" for a git identity: it sounds
like it refers to the date the PersonIdent instance was created, rather
than the date _stored in_the PersonIdent. But that is never something we
care about.
It could also be associated with with the "creation date" of a commit,
but that would also be ambiguous: it could refer either to the original
iteration of the commit (the author timestamp), or the current commit
object's creation date (the commit timestamp).
Let's just stick with "date".
Change-Id: I40d80558aeb8cb5cbad754f081e76fff616ad878
e22eb48f66