Bug 12320: Remove deprecated construct to delete cookie holdfor

Bug 12320: Remove deprecated construct to delete cookie holdfor

  $.cookie('foo', null);
is deprecated and should be replaced with
  $.removeCookie('foo');

This patch replaces the occurrences for the "holdfor" cookie.

Test plan:
1/ Search for a patron
2/ On the patron detail page, click on "search to hold"
3/ Search for records
4/ On the results page, click on "Place hold" > "Forget PATRON"
5/ Reload the page.
6/ The "Place hold" button should not contain the patron anymore

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
Works as described, no errors

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>