MODSIGN: perlify sign-file and merge in x509keyid

Turn sign-file into perl and merge in x509keyid.  The latter doesn't
need to be a separate script as it doesn't actually need to work out the
SHA1 sum of the X.509 certificate itself, since it can get that from the
X.509 certificate.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Makefile

@@ -723,7 +723,7 @@ ifeq ($(CONFIG_MODULE_SIG),y)
 MODSECKEY = ./signing_key.priv
 MODPUBKEY = ./signing_key.x509
 export MODPUBKEY
-mod_sign_cmd = sh $(srctree)/scripts/sign-file $(MODSECKEY) $(MODPUBKEY) $(srctree)/scripts/x509keyid
+mod_sign_cmd = perl $(srctree)/scripts/sign-file $(MODSECKEY) $(MODPUBKEY)
 else
 mod_sign_cmd = true
 endif