This change does not necessarily improve total performance, since the avatar is still computed.
But (1) the computation is correctly done in the work thread, not in the HTTP response thread;
(2) the computation is done just once for a given User, which could reduce load when many AJAX checks are done.

Fixing typos on French translation (in the "Administrer Jenkins" page)

- "systême" --> "système" (5 times)
- double quotes

Conflicts:
	changelog.html

Javadoc was quite confusing as the build is actually a FAILURE if tearDown returns false and not ABORTED

Conflicts:
	changelog.html

If the user still has the API token that's generated from secret.key,
don't accept that.

Hopefully this is the last fix

If JENKINS_HOME is created by a post SECURIT-49 Jenkins (LTS, and other
variants), then there's no need to alarm the user.

I look at javadoc only from IDE as a part the source code, I just won't notice package-info.java.

This is because we discovered some plugins that use Secret early on in
the initialization.