Don't resume OpenSSL DTLS session for PSK-NEGOTIATE
Don't resume OpenSSL DTLS session for PSK-NEGOTIATE

Now that we are using a custom extension instead of the session-id
hack, we no longer need to pretend to resume a session. It was causing
a session-id of 32 zeroes to be included in the ClientHello. With
OpenSSL 1.1+, that was causing fragmentation which ocserv couldn't
cope with.

Perhaps ocserv *should* have coped with that fragmentation, and perhaps
we should increase our initial idea of the MTU to avoid the fragmentation.
But certainly we shouldn't be including an all-zero session-id for
resumption either.

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

cernekee/openconnect,mtmiller/openconnect,brandt/openconnect,cernekee/openconnect,brandt/openconnect,cernekee/openconnect,nmav/openconnect-mine,nmav/openconnect-mine,nmav/openconnect-mine,mtmiller/openconnect,cernekee/openconnect,nmav/openconnect-mine,brandt/openconnect,mtmiller/openconnect,mtmiller/openconnect,brandt/openconnect