Fix fake_problem to work when periodic rerandomization is enabled

Author: dlglin

lib/WeBWorK/Utils/Tasks.pm

@@ -147,6 +147,7 @@ sub fake_problem {
 	$problem->last_answer(""); 
 	$problem->num_correct(1000); 
 	$problem->num_incorrect(1000); 
+	$problem->prCount(0);
 
 	#for my $key (keys(%{$problem})){
 	#	my $value = '####UNDEF###';