Work around more Diving Log bugs..

Work around more Diving Log bugs..

The Diving Log temperature reading is in Fahrenheit for the samples (for
the per-dive water/air temperature it's in Celsius).  But it seems to
have a bug where a lack of a sample has been turned into 32 Fahrenheit
(which is 0 celsius).  This is despite the dive itself having a water
temperature of 8 degF.

Just throw away those bogus freezing temperatures.  Sure, they can
happen, and ice divers are crazy - but in this case I know it's just an
error in the log, and it looks very much like a Diving Log bug.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>