Restore setting "disabled" on user handles of disabled users

Summary:
Fixes T3666. D6585 updated the User handles, but accidentally dropped this unusual property.

We should get rid of this -- it doesn't really make any sense on Handles -- but restore the previous beahvior to fix T3666 until we can nuke it.

Test Plan: Clicked some pages? (Actually testing this properly is a bit of a pain and I am super lazy.)

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T3666

Differential Revision: https://secure.phabricator.com/D6644