Trim the incoming activesync memo's description field.

The field is technically unlimited, but Mnemo's storage
backend may not be. Limit to a reasonable 255. This field
is normally taken from the first 64 characters of the
memo's text.

mnemo/lib/Api.php

@@ -791,7 +791,7 @@ public function replace($uid, $content, $contentType)
             break;
 
         case 'activesync':
-            $storage->modify($memo['memo_id'], $content->subject, $content->body->data, $content->categories);
+            $storage->modify($memo['memo_id'], Horde_String::substr($content->subject, 0, 255), $content->body->data, $content->categories);
             break;
 
         default: