Normally it should load more options if they exist when one scrolls to
the bottom of the list, but was not working as the 'more' bits of code
were left out.

behatnotneeded: can't test a select2 that loads data via ajax yet

Change-Id: Ica89fa229e1c9c2a1e58aa7e2d73882ffb19b65e
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>