Add cert_reqs and cadata keyword-args to ssl.wrap_socket() and
ssl.CERT_NONE, ssl.CERT_OPTIONAL, ssl.CERT_REQUIRED constants to allow
certificate validation.
CPython doesn't accept cadata in ssl.wrap_socket(), but it does in
SSLContext.load_verify_locations(), so we use this name to at least match
the same name in load_verify_locations().
Add docs for these new arguments, as well as docs for the existing
server_hostname argument which is important for certificate validation.
Tests are added as well.
Signed-off-by: Carlos Gil <carlosgilglez@gmail.com>
b41cfea02a