Deletes an Attachment.
office365.deleteAttachment(id, attachmentId, [callback])
The 'callback' parameter specifies a function which will be called when the operation completes (or an error is encountered). If the 'callback' parameter is not specified, then the method will block and will not return until the operation completes (or an error is encountered).
The callback for this method is defined as:
'err' is the error that occurred. If there was no error, then 'err' is 'null'.
'err' has 2 properties which hold detailed information:
This method deletes an attachment. id takes the ID of the message the attachment is attached to. attachmentId takes the attachment ID of an existing attachment.