Bug 5867 : Improved the email checking when sending "Hold filled" notices.

Bug 5867 : Improved the email checking when sending "Hold filled" notices.

The subroutine for sending HOLD and HOLD_PRINT notices only checked the
"email" field of the borrowers table and didn't check the value of the
AutoEmailPrimaryAddress preference. With this patch, "Hold filled"
notices can now be sent using the other email addresses of the member.

http://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=5867
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Ian Walls <ian.walls@bywatersolutions.com>