Don't suppress hallucination on/off messages when blind.
This fixes the case where you might be observing hallucinatory
monsters via telepathy yet not be told that perception was back
to normal when hallucination timed out. It does not fix the
case where temporary hallucination times out while the effect is
being blocked (in which case successful application of a unicorn
horn yields no feedback), nor the hypothetical cases where timed
hallucination starts or ends while also hallucinating for some
other reason (which could happen via polymorph someday if a
monster which is always hallucinating--the way that bats are
always stunned--ever gets introduced).
cdc0677383