Use default_md = sha1 in ``req'' section too, so we don't fallback to MD5.

Noted by smb@.

crypto/dist/openssl/apps/openssl.cnf

@@ -100,6 +100,7 @@ emailAddress		= optional
 [ req ]
 default_bits		= 1024
 default_keyfile 	= privkey.pem
+default_md		= sha1
 distinguished_name	= req_distinguished_name
 attributes		= req_attributes
 x509_extensions	= v3_ca	# The extentions to add to the self signed cert