Retrieve effectiveUserId after userId is set/re-set

Fixes: 123502937

Test: Followed steps in comment #1 of the first bug above
      Note that the test should be done with unified lock disabled, e.g.
      have separate pin/pattern/pass for owner and work profile

Change-Id: I01d66a8a1d3ed1811497c2acb7db6158d99727a0