tls_session.cpp: cleanup

authentification → authentication
chunck → chunk
DTLS
GnuTLS
IPv4
IPv6
MiM attack → MITM attack
MTU
non-reliable → unreliable
non-valid → invalid
OCSP
OK
Renogotiate → Renegotiate
retry → reattempt
shuting → shutting
tried → attempt
try → attempt
URI
x509 → X.509

Change-Id: I5ab67f1fb10b24aa8de79217cba219137de6a88b