coverity: Suppress weak_crypto errors

None of random/rand is used in security context but they are reported by
coverity and makes debugging of real issues pretty hard.

So this patch uses coverity specific comment to suppress these type
of errors.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Christine Caulfield <ccaulfie@redhat.com>