Fix bug in implementation

Previously when the transaction errored it would not exit and would leave the transaction
open. Now it exits correctly when an exception is seen during the message transaction.

Author: hmstepanek

newrelic/hooks/messagebroker_kombu.py

@@ -169,7 +169,9 @@ def wrap_consumer_recieve_callback(wrapped, instance, args, kwargs):
     try:
         return_val = wrapped(*args, **kwargs)
     except Exception:
-        if current_transaction():
+        if created_transaction:
+            created_transaction.__exit__(*sys.exc_info())
+        elif current_transaction():
             # Report error on existing transaction if there is one
             notice_error()
         else: