digsig: improve comment explaining g_init

Improve the comment explaining the purpose of the g_init variable.

Signed-off-by: Rupert Muchembled <rupert@rmuch.net>
digsig: remove space between macro name and paren

Remove space between function/macro name and parenthesis, reported by
checkpatch.pl.

Signed-off-by: Rupert Muchembled <rupert@rmuch.net>