Bug 12143 - hiding alternate address on patron self registration doesn't hide heading

This patch fixes the following issue: in OPAC self registration form,
even if all alternate address fields are configured as hidden,
the heading for "Alternate address" still shows.

To test:

1/ Confirm the issue: hide all alternate adres field names (i.e., enter
B_address|B_address2|B_city|B_state|B_zipcode|B_country|B_phone|
B_email|contactnote into PatronSelfRegistrationBorrowerUnwantedField
system prefrence).
2/ Observe that "Alternate address" section heading still shows
in patron self registration form ("your personal details" tab),
despite that all section fields are configured as hidden.
3/ Apply patch.
4/ Reload OPAC self registration form; confirm that "Alternate address"
is not displyed any longer, and the issue is now fixed.
5/ Remove some field name (e.g. B_address2) from
PatronSelfRegistrationBorrowerUnwantedField; ensure that "Alternate
address" heading does show if at least one section field is not
hidden.
6/ Test steps 1-5 should be performed/repeated in both bootstrap
and prog OPAC themes.

Followed test plan with prog and bootstrap themes, works as expected.
Signed-off-by: Marc Véron <veron@veron.ch>

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>