Clean up DTLS cipher selection for OpenSSL >= 1.1.0
Clean up DTLS cipher selection for OpenSSL >= 1.1.0

Where we have SSL_get1_supported_ciphers(), use it to generate the list we
advertise to the server in the first place. This stops us from advertising
DES support when we're not really going to do it, for example.

Signed-off-by: David Woodhouse <97b3379caa91f4ee97e44013ae4dc6350540fa9d@infradead.org>

brandt/openconnect,brandt/openconnect,brandt/openconnect,brandt/openconnect