RT2626: Change default_bits from 1K to 2K

This is a more comprehensive fix.  It changes all
keygen apps to use 2K keys. It also changes the
default to use SHA256 not SHA1.  This is from
Kurt's upstream Debian changes.

Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Kurt Roeckx <kurt@openssl.org>

apps/openssl.cnf

diff --git a/apps/openssl.cnf b/apps/openssl.cnf
index 514e640..41c2a37 100644
--- a/apps/openssl.cnf
+++ b/apps/openssl.cnf
@@ -103,7 +103,7 @@
 
 ####################################################################
 [ req ]
-default_bits		= 1024
+default_bits		= 2048
 default_keyfile 	= privkey.pem
 distinguished_name	= req_distinguished_name
 attributes		= req_attributes