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