Horde_Mail_Rfc822 already takes care of array conversion for us
[mms] Correctly encode IDN domains when sending mail (Bug #12116).
Add missing value for sprintf.
Actually return the public s/mime key.

Fixes/enables SENDING s/mime encrypted emails to recipients whose
public keys are locatable in the global address book.
CHANGES
Merge branch 'master' into horde_5_1