LP1951642 Self-registration DOB autopopulating date

LP1951642 Self-registration DOB autopopulating date

This removes the autopopulation of the dob date in the opac's
self-registration page.

To test:

1. In library settings turn on "Allow Patron Self-Registration" and "Show dob
field in patron registration". "Require dob field on patron registration"
can also be turned on to test that option.

2. Go to the "Request Library Card" page of the opac and notice that the
dob field is populated with today's date.

3. Apply the patch.

4. Check the dob field again and notice that it is no longer autopopulated.

5. Create a few registrations with dob dates and with no dob dates to confirm
that the field works.

Signed-off-by: Garry Collum <gcollum@gmail.com>