Log Message:
Add a buildlink dependency on openssl to couriertcpd, which needs the
SSL libraries to build couriertls, which encapsulates the logic for
handling SSL connections for Courier services.  Drop the dependency
on openssl from both courier-imap and courier-mta, which only need
the "openssl" tool instead.  Bump the PKGREVISIONs for all three
packages due to the changed dependencies.  Problem noted by Ondrej
Tuma in private email.