Bug 21390: Send registration verification emails immediately

Bug 21390: Send registration verification emails immediately

To test
1/ Enable self registration
2/ Register, notice message is queued in the table but not sent
3/ Apply patch
4/ Register again, notice message is queued, but immediately sent

Sponsored by: Goethe-Institut
Signed-off-by: Maryse Simard <maryse.simard@inlibro.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
(cherry picked from commit 957d583d2efce66e31fe05f229fda91c58324bc2)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>