Bug 1761037: Commit the email update on first install correctly

Rather than update db directly - we need to update the USER object

behatnotneeded

Change-Id: I31f8c6759dd621439c90ddc0f0dc8a344359d5d9
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>
(cherry picked from commit 4adf4a01)
(cherry picked from commit 6905c539)