Source syncing tweaks. (#705)

* Allow owner to be specified when syncing certs.

* Ensuring non-endpoint plugins don't fail to complete syncing.

* Adding in some additional error handling.

lemur/sources/service.py

@@ -67,7 +67,7 @@ def sync_endpoints(source):
         endpoints = s.get_endpoints(source.options)
     except NotImplementedError:
         current_app.logger.warning("Unable to sync endpoints for source {0} plugin has not implemented 'get_endpoints'".format(source.label))
-        return
+        return new, updated
 
     for endpoint in endpoints:
         exists = endpoint_service.get_by_dnsname(endpoint['dnsname'])
@@ -114,7 +114,9 @@ def sync_certificates(source, user):
     for certificate in certificates:
         exists = certificate_service.get_by_name(certificate['name'])
 
-        certificate['owner'] = user.email
+        if not certificate.get('owner'):
+            certificate['owner'] = user.email
+
         certificate['creator'] = user
 
         if not exists: