test-routing-request: Use the right unref function

Use `g_ptr_array_unref()` instead of `g_array_unref()` on `GPtrArray`
instances. This got caught by the new GCC 8 warnings.

Signed-off-by: Emanuele Aina <emanuele.aina@collabora.com>

tests/test-routing-request.c

@@ -296,7 +296,7 @@ test_builder (void)
 
   parameters = trp_routing_request_get_parameters (request);
   g_assert_cmpint (parameters->len, ==, 0);
-  g_clear_pointer (&parameters, g_array_unref);
+  g_clear_pointer (&parameters, g_ptr_array_unref);
 
   parameters = trp_routing_request_get_points (request);
   g_assert_cmpint (parameters->len, ==, 1);
@@ -305,7 +305,7 @@ test_builder (void)
   place = trp_routing_parameter_get_place (parameter);
   g_assert_true (place == norwich);
   g_clear_object (&place);
-  g_clear_pointer (&parameters, g_array_unref);
+  g_clear_pointer (&parameters, g_ptr_array_unref);
 
   g_clear_object (&request);
 
@@ -371,7 +371,7 @@ test_builder (void)
   g_assert_true (place == norwich);
   g_clear_object (&place);
 
-  g_clear_pointer (&parameters, g_array_unref);
+  g_clear_pointer (&parameters, g_ptr_array_unref);
 
   parameters = trp_routing_request_get_parameters (request);
   g_assert_cmpint (parameters->len, ==, 7);
@@ -416,7 +416,7 @@ test_builder (void)
   g_assert_true (place == norwich);
   g_clear_object (&place);
 
-  g_clear_pointer (&parameters, g_array_unref);
+  g_clear_pointer (&parameters, g_ptr_array_unref);
 
   notes = trp_routing_request_get_parameter_values (request, "X-MY-NOTE");
   g_assert_nonnull (notes);