Bug#746201: Actual problem is bogus error message

[Jonathan Hutchins]

Error message is bogus, problem is that spamassassin + exim4 does not
install exim4-daemon-heavy, and exim4-daemon-light does not acknowledge
the configuration for spamassassin.  It might be helpful to require -heavy
or to at least give informative messages.  Recommends does not appear to
be an adequate solution.  This remains a bug as it allows a disfunctional
install.