Remove deprecated OpenSSL methods

TLSv1_2_METHOD and SSLv23_METHOD are deprecated in OpenSSL [0], update
SSL.Context to use the generic TLS_METHOD.

This change also fixes the c9s-based FIPS jobs (they don't support
TLSv1.2).

[0] https://www.pyopenssl.org/en/stable/api/ssl.html#context-objects

Story 2009942
Task 44847

Change-Id: I39e293db39d2a9287b581833cfe9fd469f701a7c
1 file changed