build: add load_needed_modules.py.in to EXTRA_DIST

Change-Id: Ie8e3fd1f8a6b3ce5c96dbb4cde5e61f3d2cba4d9
Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/12507
Reviewed-by: Kiril Nesenko <knesenko@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>