Review can't be selected even though review limit has not been reached.

[efg]

Nathan Sudduth reports that he can't do a second review. I checked and found that the review limit (15) had not been reached; submissions had 8 or 9 reviews. Why not? We are suspicious of line 117 in review_assignment.rb, which is supposed to reject submissions that have more than the minimum number of reviews. It may be rejecting too many submissions (in this case, all submissions).