Update a comment for test2.15

testsuite/expect/test2.15

@@ -60,7 +60,8 @@ if {$available < $node_cnt} {
 	send_user "\nWARNING: not enough nodes currently available ($available avail, $node_cnt needed)\n"
 	exit $exit_code
 }
-
+#For this test set KillOnBadExit to the default value 0 otherwise the
+#tes will fail giving a false positive.
 # NOTE: The second sleep command in task 1 is to deal with a possible race
 # condition in which the first sleep command is killed and the shell starts the
 # second command before the shell itself is killed