Bug 12633: Remove SQLHelper in C4::Members

Bug 12633: Remove SQLHelper in C4::Members

This is the only places where SQLHelper is still called.
The C4::Members::Search is not used anymore, but ModMember and
AddMember.

This patch replaced the calls to SQLHelper to use DBIX::Class.
TODO: Move them to Koha::Borrower.

Test plan:
1/ Make sure the patron search still works (no changes expected since the
code was not in used).
2/ Add a patron with all fields filled
3/ Add another patron with some fields filled
4/ Update them with other values
5/ Delete them

You should not get any errors.

Signed-off-by: Mirko Tietgen <mirko@abunchofthings.net>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>