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>