Truncate file first, just in case new file is shorter.
Truncate file first, just in case new file is shorter.

Signed-off-by: Jon Seymour <44f878afe53efc66b76772bd845eb65944ed8232@wildducktheories.com>

eightyeight/gosunspec,crabmusket/gosunspec,jonseymour/gosunspec