Error when email addresses are separated by ;

[ngm]

As originally reported here: https://talk.restarters.net/t/bug-report-creating-a-user-group-fails/313/5

I see this error in the logs: Address in mailbox given [info@maakbaarleuven.be;wg_repairapp@maakbaarleuven.be] does not comply with RFC 2822

It looks like two email addresses have ended up combined by a ; - not sure how that happened but we’ll add something in to trap that and report to user rather than giving an exception.