Fixing an IAM syncing issue. Were duplicates were not properly sync'd… (#638)

* Fixing an IAM syncing issue. Were duplicates were not properly sync'd with Lemur. This resulted in a visibility gap. Even 'duplicates' need to sync'd to Lemur such that we can track rotation correctly. Failing on duplicates lead to missing those certificates and the endpoints onto which they were deployed. This commit removes the duplicate handling altogether.

* Fixing tests.

lemur/plugins/lemur_aws/elb.py

@@ -10,6 +10,7 @@ from flask import current_app
 
 from retrying import retry
 
+from lemur.extensions import metrics
 from lemur.exceptions import InvalidListener
 from lemur.plugins.lemur_aws.sts import sts_client
 
@@ -22,11 +23,12 @@ def retry_throttled(exception):
     """
     if isinstance(exception, botocore.exceptions.ClientError):
         if exception.response['Error']['Code'] == 'LoadBalancerNotFound':
-            return
+            return False
 
         if exception.response['Error']['Code'] == 'CertificateNotFound':
-            return
+            return False
 
+    metrics.send('ec2_retry', 'counter', 1)
     return True