Real time memeber roles sync doesn't work for bulk membership imports + patch

I was expecting the import to immediately cause Drupal's roles to update as part of the import process. Not the case, even though this is vital as with the real time option selected, the cron etc won't run.

To fix it, I've added a call to the sync function after a membership import job has finished. This may be a little intensive, but so is an import job and the alternative is that the sync never happens.