added exit code 1 when failed to deliver records (#6)

Signed-off-by: Francisco Vila <fvila@redhat.com>

Author: franvila

Producer.py

@@ -31,6 +31,7 @@ def main(args):
     def delivery_callback(err, msg):
         if err:
             sys.stderr.write('%% Record failed delivery: %s\n' % err)
+            sys.exit(1)
         else:
             print('Record {} successfully produced to {} [{}] at offset {}'.format(
                 msg.key(), msg.topic(), msg.partition(), msg.offset()))