Tweak SSL client method selection for OpenSSL 1.1.1

Connections via TLSv1.3 will actually not include a timestamp, so the
change to use TLS_client_method() for OpenSSL 1.1 builds broke
tlsdate. Revert that part to use explicit client methods again. While
at it, add choices for TLSv1.1 and TLSv1.2 and use the latter by
default.

BUG=chromium:736583
TEST=platform_TLSDateActual succeeds both with OpenSSL 1.0.2 and 1.1.1

Change-Id: I07d3541770cf1219b9d095a5d60456a3c4ae356d
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/tlsdate/+/1997498
Tested-by: Mattias Nissler <mnissler@chromium.org>
Auto-Submit: Mattias Nissler <mnissler@chromium.org>
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Commit-Queue: Mattias Nissler <mnissler@chromium.org>
4 files changed