fixing thread blocking issue when a connectivity issue with the backend

git-svn-id: https://svn.apache.org/repos/asf/synapse/trunk@1763068 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/java/modules/transports/core/nhttp/src/main/java/org/apache/synapse/transport/passthru/DeliveryAgent.java b/java/modules/transports/core/nhttp/src/main/java/org/apache/synapse/transport/passthru/DeliveryAgent.java
index 6ac5792..38ab070 100644
--- a/java/modules/transports/core/nhttp/src/main/java/org/apache/synapse/transport/passthru/DeliveryAgent.java
+++ b/java/modules/transports/core/nhttp/src/main/java/org/apache/synapse/transport/passthru/DeliveryAgent.java
@@ -145,6 +145,11 @@
                 }
                 targetErrorHandler.handleError(msgCtx, errorCode, errorMessage,
                         null, ProtocolState.REQUEST_READY);
+                synchronized (msgCtx) {
+                    msgCtx.setProperty(PassThroughConstants.WAIT_BUILDER_IN_STREAM_COMPLETE,
+                                       Boolean.TRUE);
+                    msgCtx.notifyAll();
+                }
             }
         } else {
             throw new IllegalStateException("Queue cannot be null for: " + key);