Add SSL_CIPHER_get_kx_name.

This is needed by Android because it passes this string to a handshake
callback. It's implemented in Android's OpenSSL in this patch:
  https://android.googlesource.com/platform/external/openssl.git/+/master/patches/0003-jsse.patch

(Note that it's called |SSL_authentication_method| there.)

I didn't format this function in OpenSSL style because it's crazy and
because we'll probably clang-format ssl/ soon.

Change-Id: I865540511b50859c339da5d76ce37810449aa444
2 files changed