Increase maximum size of X.509 certificate
Increase maximum size of X.509 certificate

2048 bytes isn't quite enough for my VPN certs. Ideally this should be
dynamically allocated but just increasing it to 4096 will probably suffice
for now.

Signed-off-by: David Woodhouse <b460d66aaf00c296a3db1c1d9eeafc081d5f7d70@intel.com>

mtrojnar/libp11,mouse07410/libp11,nmav/libp11,gerow/libp11,mouse07410/libp11,nmav/libp11,OpenSC/libp11,dengert/libp11,gerow/libp11,mtrojnar/libp11,dengert/libp11,OpenSC/libp11