fix flow. cleanup takes no args, remove err

Author: NickOvt

lib/handlers/on-copy.js

@@ -289,15 +289,18 @@ async function copyHandler(server, messageHandler, connection, mailbox, update,
                                                     key => prepared.mimeTree.attachmentMap[key]
                                                 );
 
-                                                messageHandler.attachmentStorage.deleteManyAsync(attachmentIds, maildata.magic).catch(err => reject(err));
-
-                                                if (err) {
-                                                    return reject(err);
-                                                }
+                                                messageHandler.attachmentStorage
+                                                    .deleteManyAsync(attachmentIds, maildata.magic)
+                                                    .then(() => {
+                                                        if (err) {
+                                                            return reject(err);
+                                                        }
+                                                    })
+                                                    .catch(error => reject(error));
                                             };
 
                                             if (err) {
-                                                return cleanup(err);
+                                                return cleanup();
                                             }
 
                                             return resolve(prepared);