Do not try to establish DTLS on reconnect if it wasn't established before

Do not try to establish DTLS on reconnect if it wasn't established before

Currently when TCP SSL fails reconnect attempt happens. This attempts tries to establish DTLS connection regadless if it existed before. Code ends up in infinite loop doing that.
This changes fixes this by disabling DTLS at startup if DTLS connection cannot be established.
Also change ESP handling code to not reenable DTLS on ESP close.

Signed-off-by: Nikolay Martynov <mar.kolya@gmail.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>