do not disable trigger on 409 (conflict) (#168)

diff --git a/provider/lib/utils.js b/provider/lib/utils.js
index 1ebe486..ef0717c 100644
--- a/provider/lib/utils.js
+++ b/provider/lib/utils.js
@@ -156,7 +156,7 @@
 
     function shouldDisableTrigger(statusCode) {
         return ((statusCode >= 400 && statusCode < 500) &&
-            [HttpStatus.REQUEST_TIMEOUT, HttpStatus.TOO_MANY_REQUESTS].indexOf(statusCode) === -1);
+            [HttpStatus.REQUEST_TIMEOUT, HttpStatus.TOO_MANY_REQUESTS, HttpStatus.CONFLICT].indexOf(statusCode) === -1);
     }
 
     function shouldFireTrigger(trigger) {