Bug 15412: Enable dropdowns date selector when suspending holds

 Bug 15412: Enable dropdowns date selector when suspending holds

It seems to be the way to fix that
https://stackoverflow.com/questions/13649459/twitter-bootstrap-multiple-modal-error

Test plan:
1 - Place a hold through the opac
2 - View your account->Holds
3 - Click suspend hold
4 - You should be able to select a date using the arrows and dropdowns

Followed test plan, works as expected.
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Brendan A Gallagher <brendan@bywatersolutions.com>
(cherry picked from commit 01d48a78258f98f693a8f48d7294a6ae880d5fc4)
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>