CamelGpgContext: Enclose email addresses in brackets.
The recipient list for encrypting can be specified by either key ID or email address. Enclose email addresses in brackets to ensure an exact match, as per the gpg man page: HOW TO SPECIFY A USER ID ... By exact match on an email address. This is indicated by enclosing the email address in the usual way with left and right angles. <firstname.lastname@example.org> Without the brackets gpg uses a substring match, which risks selecting the wrong recipient. (cherry picked from commit 5d8b92c6)