Bug 1282109: update kinto-offline-client.js, r=MattN

MozReview-Commit-ID: BiE4UvlLu6T

Author: Ethan Glasser-Camp

services/common/blocklist-clients.js

@@ -69,7 +69,7 @@ function mergeChanges(localRecords, changes) {
 
 function fetchCollectionMetadata(collection) {
   const client = new KintoHttpClient(collection.api.remote);
-  return client.bucket(collection.bucket).collection(collection.name).getMetadata()
+  return client.bucket(collection.bucket).collection(collection.name).getData()
     .then(result => {
       return result.signature;
     });