Fix getMoreHistory to not return lastKnownHash

www/common/sframe-common-mailbox.js

@@ -180,7 +180,7 @@ define([
             var txid = Util.uid();
             execCommand('LOAD_HISTORY', {
                 type: type,
-                count: count,
+                count: lastKnownHash ? count + 1 : count,
                 txid: txid,
                 lastKnownHash: lastKnownHash
             }, function (err, obj) {
@@ -195,6 +195,7 @@ define([
                     historyState = false;
                     return;
                 }
+                if (data.hash !== lastKnownHash) {
                     messages.push({
                         type: type,
                         content: {
@@ -203,6 +204,7 @@ define([
                             hash: data.hash
                         }
                     });
+                }
             };
         };
         mailbox.getNotificationsHistory = function (type, count, lastKnownHash, cb) {