Remove unnecessary promise wrapper

src/converse-omemo.js

@@ -258,13 +258,9 @@
 
                 getEncryptionAttributesfromStanza (stanza, original_stanza, attrs) {
                     const { _converse } = this.__super__,
-                          encrypted = sizzle(`encrypted[xmlns="${Strophe.NS.OMEMO}"]`, original_stanza).pop();
-
-                    return new Promise((resolve, reject) => {
-                        const { _converse } = this.__super__,
+                          encrypted = sizzle(`encrypted[xmlns="${Strophe.NS.OMEMO}"]`, original_stanza).pop(),
                           header = encrypted.querySelector('header'),
                           key = sizzle(`key[rid="${_converse.omemo_store.get('device_id')}"]`, encrypted).pop();
-
                     if (key) {
                         attrs['encrypted'] = {
                             'device_id': header.getAttribute('sid'),
@@ -273,11 +269,10 @@
                             'payload': _.get(encrypted.querySelector('payload'), 'textContent', null),
                             'prekey': key.getAttribute('prekey')
                         }
-                            this.decrypt(attrs)
-                                .then((plaintext) => resolve(_.extend(attrs, {'plaintext': plaintext})))
-                                .catch(reject);
+                        return this.decrypt(attrs);
+                    } else {
+                        return Promise.resolve(attrs);
                     }
-                    });
                 },
 
                 getMessageAttributesFromStanza (stanza, original_stanza) {