Bug 18438 - Implemented data-dismiss="modal" in returns.tt so that any warning messag...

Bug 18438 - Implemented data-dismiss="modal" in returns.tt so that any warning messages hidden by a hold modal are displayed after it is dismissed

Test plan:
1. Check out an item to one patron whilst having that item also being on
hold to another patron

2. Check the item back in

3. Notice a modal box appears greying out the background with three
buttons 'Confirm hold', 'Print and confirm' and 'Ignore'. Click confirm
and notice that the page refreshes and no yellow warning messages are
able to be displayed

4. Now that you have checked the item in. Try checking it in a second
time by clicking on the Checkin tab and writing in the barcode.

5. The modal box will appear again, this time with three buttons
'Confirm', 'Print and confirm' and 'Cancel hold'

6. Click the 'Confirm' button and the page refreshes again and the
yellow warning message hidden by the modal box is not properly displayed
to the user. Notice that the focus is on the barcode input box.

7. Apply patch

8. Try checking in the item again, and this time after clicking the
'confirm' button on the modal box notice that the yellow warning message
is displayed telling the user the item was "Not checked out". Also
notice the focus is in the barcode inputbox.

9. Drop the hold on the item and make sure it is not checked out.

10. Repeat steps 1 and 2 and notice after clicking the 'Confirm hold'
button the page refreshes and the item is successfully checked back in.
With the focus on the barcode input.

11. View koha-tmpl/intranet-tmpl/prog/en/modules/circ/returns.tt and
notice that the button on line 345 does not use an onclick parameter

Followed test plan, works as expected.
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Amended-patch: remove spaces

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>