fix out-of-bounds check in lock_dbg_cb (was too lose to detect all
invalid cases)

PR: 674
diff --git a/ssl/ssltest.c b/ssl/ssltest.c
index a304398..7bb4152 100644
--- a/ssl/ssltest.c
+++ b/ssl/ssltest.c
@@ -303,7 +303,7 @@
 		goto err;
 		}
 
-	if (type < 0 || type > CRYPTO_NUM_LOCKS)
+	if (type < 0 || type >= CRYPTO_NUM_LOCKS)
 		{
 		errstr = "type out of bounds";
 		goto err;