remove callback based deleteMany from attachment storage. In on-copy.js use async version

Author: NickOvt

lib/attachment-storage.js

@@ -36,18 +36,6 @@ class AttachmentStorage {
         return this.storage.createReadStream(id, attachmentData, options);
     }
 
-    deleteMany(ids, magic, callback) {
-        let pos = 0;
-        let deleteNext = () => {
-            if (pos >= ids.length) {
-                return callback(null, true);
-            }
-            let id = ids[pos++];
-            this.delete(id, magic, deleteNext);
-        };
-        deleteNext();
-    }
-
     updateMany(ids, count, magic, callback) {
         return this.storage.update(ids, count, magic, callback);
     }

lib/handlers/on-copy.js

@@ -289,7 +289,7 @@ async function copyHandler(server, messageHandler, connection, mailbox, update,
                                                     key => prepared.mimeTree.attachmentMap[key]
                                                 );
 
-                                                messageHandler.attachmentStorage.deleteMany(attachmentIds, maildata.magic, () => {});
+                                                messageHandler.attachmentStorage.deleteManyAsync(attachmentIds, maildata.magic);
 
                                                 if (err) {
                                                     return reject(err);