keygeneration: make the certificates valid for 10 years

UEFI firmware implementations are unlikely to validate the "days".
However we'd better specify a reasonable value. We learned that
setting the "days" argument to a large number can cause unexpected
results due to overflow.

GCE team has decided to set this value as 10 years.

BUG=b:62189155
TEST=None
BRANCH=none

Change-Id: If0375251b41e9584708355a6fd32192aa5ad0c1a
Reviewed-on: https://chromium-review.googlesource.com/1088165
Commit-Ready: Edward Jee <edjee@google.com>
Tested-by: Edward Jee <edjee@google.com>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed