tests: Use error probability model instead of SNR model

If wmediumd changes its SNR model, these tests need to be modified (ex.
previously SNR = 0 means disconnection, on the new model, SNR should be
-10 for disconnection). So use error probability model not to be
influenced by SNR model change.

Signed-off-by: Masashi Honma <masashi.honma@gmail.com>

tests/hwsim/test_wmediumd.py

@@ -28,11 +28,16 @@ CFG2 = """
 ifaces :
 {
     ids = ["%s", "%s", "%s"];
+};
+
+model:
+{
+    type = "prob";
 
     links = (
-        (0, 1, 50),
+        (0, 1, 0.000000),
-        (0, 2, 50),
+        (0, 2, 0.000000),
-        (1, 2, -10)
+        (1, 2, 1.000000)
     );
 };
 """