Correct bug where Grades.pm writes problem_user data when it should not

Fix Grades.pm so that it only updates problem_user records if they are actually broken

Author: dlglin

lib/WeBWorK/ContentGenerator/Grades.pm

@@ -498,14 +498,14 @@ sub grade_set {
 		    my  $attempted    = $problemRecord->attempted;
 			my $num_correct   = $problemRecord->num_correct || 0;
 			my $num_incorrect = $problemRecord->num_incorrect   || 0;
-			$num_of_attempts  = $num_correct + $num_incorrect;
+			$num_of_attempts  += $num_correct + $num_incorrect;
 
 #######################################################
 			# This is a fail safe mechanism that makes sure that
 			# the problem is marked as attempted if the status has
 			# been set or if the problem has been attempted
 			# DBFIXME this should happen in the database layer, not here!
-			if (!$attempted && ($status || $num_of_attempts)) {
+			if (!$attempted && ($status || $num_correct || $num_incorrect )) {
 				$attempted = 1;
 				$problemRecord->attempted('1');
 				# DBFIXME: this is another case where it