[3.7] bpo-30622: Improve NPN support detection (GH-5859) (#5860)

The ssl module now detects missing NPN support in LibreSSL.

Co-Authored-By: Bernard Spil <brnrd@FreeBSD.org>
Signed-off-by: Christian Heimes <christian@python.org>
(cherry picked from commit 6cdb7954b0a578d899e4b78b868ea59eef08480a)

Co-authored-by: Christian Heimes <christian@python.org>
4 files changed