Fix water temperature on Suunto SDM import

Seems that Suunto stores temperature value of 0 when there is no
temperature reading (I guess). Thus this patch ignores temperature
samples that are zero. Otherwise, Subsurface looks into the samples and
grabs the lowest number as water temperature.

See #720

Signed-off-by: Miika Turkia <miika.turkia@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Latest Portuguese translations

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>