[dev] Patch for hiding invite link

[Chuck Hagenbuch]

Quoting Jason Rust <jrust at rustyparts.com>:

> Attached is a patch that hides the Invite link on the view event page if
> the user has no valid email addresses in their list of identities.
> Since the user would not be able to send an invite anyhow if they have
> no valid from_adresses it saves them the confusion and trouble of trying
> to invite someone to an event.

Committed, thanks.

-chuck

--
Charles Hagenbuch, <chuck at horde.org>
The alligators were there, too, in a bathtub inside the house.