ut_call: use refuseCall, not hangup to decline

Else, the closing is not guaranteed due to potential 481 errors when invite is
deleted before the message sent.

Change-Id: I7e02b55c7967e336ca6357869034103a36ecb262
GitLab: #559

test/unitTest/call/call.cpp

@@ -281,7 +281,7 @@ CallTest::testDeclineMultiDevice()
 
     JAMI_INFO("Stop call between alice and Bob");
     callStopped = 0;
-    Manager::instance().hangupCall(callIdBob);
+    Manager::instance().refuseCall(callIdBob);
     CPPUNIT_ASSERT(cv.wait_for(lk, std::chrono::seconds(30), [&] {
         return callStopped.load() >= 3; /* >= because there is subcalls */
     }));