Fix the problem where the tx cannot run after ack_failure

The reason of the test failure was that the roll_back is not sent to the server to terminate current tx.
So the next run will just inject into previous tx.

Author: Zhen

driver/src/main/java/org/neo4j/driver/internal/InternalSession.java

@@ -148,7 +148,7 @@ public void run()
                 //must check if transaction has been closed
                 if (currentTransaction != null)
                 {
-                    currentTransaction.markAsRolledBack();
+                    currentTransaction.failure();
                     currentTransaction = null;
                     connection.onError( null );
                 }

driver/src/main/java/org/neo4j/driver/internal/InternalTransaction.java

@@ -112,8 +112,6 @@ public void close()
                 }
                 else if ( state == State.MARKED_FAILED || state == State.ACTIVE )
                 {
-                    // If alwaysValid of the things we've put in the queue have been sent off, there is no need to
-                    // do this, we could just clear the queue. Future optimization.
                     conn.run( "ROLLBACK", Collections.<String, Value>emptyMap(), StreamCollector.NO_OP );
                     conn.discardAll();
                     conn.sync();
@@ -171,6 +169,8 @@ public StatementResult run( Statement statement )
         }
         catch ( Neo4jException e )
         {
+            // Failed to send messages to the server probably due to IOException in the socket.
+            // So we should stop sending more messages in this transaction
             state = State.FAILED;
             throw e;
         }
@@ -200,12 +200,5 @@ public TypeSystem typeSystem()
         return InternalTypeSystem.TYPE_SYSTEM;
     }
 
-    // TODO: This is wrong. This is only needed because we changed the SSM
-    // to move to IDLE on any exception (so the normal `ROLLBACK` statement won't work).
-    // We should change the SSM to move to some special ROLLBACK_ONLY state instead and
-    // remove this code path
-    public void markAsRolledBack()
-    {
-        state = State.ROLLED_BACK;
-    }
+
 }

driver/src/test/java/org/neo4j/driver/v1/integration/ResultStreamIT.java

@@ -23,7 +23,6 @@
 
 import org.neo4j.driver.v1.Record;
 import org.neo4j.driver.v1.StatementResult;
-import org.neo4j.driver.v1.types.Node;
 import org.neo4j.driver.v1.util.TestNeo4jSession;
 
 import static org.junit.Assert.assertEquals;
@@ -62,20 +61,6 @@ public void shouldHaveFieldNamesInResult()
         assertEquals( "[n]", res.keys().toString() );
     }
 
-    @Test
-    public void should()
-    {
-        // When
-        StatementResult res = session.run( "CREATE (n:TestNode {name:'test', prop: [42]}) RETURN n" );
-
-        Node n = res.next().get( "n" ).asNode();
-        System.out.println( n );
-        // Then
-        assertEquals( "[n]", res.keys().toString() );
-        assertNotNull( res.single() );
-        assertEquals( "[n]", res.keys().toString() );
-    }
-
     @Test
     public void shouldGiveHelpfulFailureMessageWhenAccessNonExistingField() throws Throwable
     {