system cfg: set mkpasswd default to SHA256

This patch changes the default mkpasswd method to SHA256 from MD5.
The change both improves the quality of the hash used and prepares
for eventually removing MD5 as a option.

Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
1 file changed