Bug 31251: Use jQuery val() to clear_entry

Bug 31251: Use jQuery val() to clear_entry

1. Add some patron attributes that are textarea and some that have an AV category so they are select dropdowns
2. Go to the patron form and add some values to the patron attributes
3. Use the "Clear" button to try and clear the values, doesnt work.
4. Apply patch
5. Try clearing values from patron attributes that are both select dropdowns and textarea. The "Clear" button should work.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit a3198f647496d87e19036432f1be9f87dac4614d)

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
(cherry picked from commit 25b2ebf8b25c52078c3c5bb5a50af0c5dab31039)
Signed-off-by: Arthur Suzuki <arthur.suzuki@biblibre.com>