Refactor session polling (#314)

functional-tests/src/main/scala/com/vertica/spark/functests/EndToEndTests.scala

@@ -4148,24 +4148,24 @@ class EndToEndTests(readOpts: Map[String, String], writeOpts: Map[String, String
 
     // Poll sessions until they have cleaned up (or until we give up)
     var success: Boolean = false
-    var i: Int = 0
-    while (!success || i < 10) {
+    var i: Int = 1
+    while (!success && i <= 10) {
+      Thread.sleep(1000)
       val stmt = conn.createStatement()
       val query = "SELECT COUNT(*) FROM v_monitor.sessions;"
       try {
         val rs = stmt.executeQuery(query)
         rs.next
         // Expect a single session for the session count query itself
         // Note that this can fail if you are connected to vsql or performing other operations on the DB at the same time as these tests
-        success = (rs.getInt(1) == 1)
+        success = (rs.getInt(1) <= 1)
       } catch {
         case err : Exception => fail(err)
       } finally {
         stmt.close()
       }
       println("Unexpected session count, trying again - iteration " + i)
       i += 1
-      Thread.sleep(1000)
     }
     assert(success)