Remove unpatched select2 JS files from git repo

[Aaron Wells]

We've got four select2 Javascript files in Mahara core under htdocs/js/select2:

1. select2.full.js: Select2 plus some compatibility & "recommended includes" modules
2. select2.full.min.js: Minified version of above
3. select2.js: Standard version of select2
4. select2.min.js: Minified version of above.

We actually only use one of these, select2.full.js. And, we have applied several patches to that file! So we really ought to remove the other files, to prevent a developer from accidentally writing new code that uses one of them, bypassing our patches.

[Mahara Bot (dev-mahara)]

Patch for "master" branch: https://reviews.mahara.org/6015

[Mahara Bot (dev-mahara)]

Reviewed: https://reviews.mahara.org/6015
Committed: https://git.mahara.org/mahara/mahara/commit/7911f429bdc63ee68d52acb9090fbb98b533d312
Submitter: Robert Lyon (<email address hidden>)
Branch: master

commit 7911f429bdc63ee68d52acb9090fbb98b533d312
Author: Aaron Wells <email address hidden>
Date: Thu Feb 4 18:01:34 2016 +1300

Removing unused select2 Javascript files (Bug 1541684)

Removing these to prevent developers from accidentally using
them; since we haven't been applying our custom patches to
them.

behatnotneeded: Covered by existing tests

Change-Id: Ic4a542d1e1d122cbb7735afb6b5205ca051045a9