Fix bug in assignment.php: if we find no eligible chugim or campers, we should not consider it an error condition.  We should keep going and assign blocks that do have at least one camper and chug available.
Fix bug in assignment.php: if we find no eligible chugim
or campers, we should not consider it an error condition.  We
should keep going and assign blocks that do have at least one camper and chug
available.

dlobron/ChugBot,dlobron/ChugBot,dlobron/ChugBot,dlobron/ChugBot