Fix StreamingListenerSuite's startedReceiverStreamIds size

Author: ilayaperumalg

streaming/src/test/scala/org/apache/spark/streaming/StreamingListenerSuite.scala

@@ -74,7 +74,7 @@ class StreamingListenerSuite extends TestSuiteBase with Matchers {
     ssc.start()
     try {
       eventually(timeout(1000 millis), interval(20 millis)) {
-        collector.startedReceiverStreamIds.size should be >= 1
+        collector.startedReceiverStreamIds.size should equal (1)
         collector.startedReceiverStreamIds(0) should equal (0)
         collector.stoppedReceiverStreamIds should have size 1
         collector.stoppedReceiverStreamIds(0) should equal (0)