Issue #21015: SSL contexts will now automatically select an elliptic curve for ECDH...

(should also fix a buildbot failure introduced by #20995)

diff --cc Misc/NEWS
index ade246c340b252ac149a9bd23f35bc29be09c67d,6b527ea440614b62d624769058d5b676fcd1ab9b..15479393fab4d59a46b4444595eafada3825a6be
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -23,8 -21,10 +23,12 @@@ Core and Builtin
  Library
  -------
  
+ - Issue #21015: SSL contexts will now automatically select an elliptic
+   curve for ECDH key exchange on OpenSSL 1.0.2 and later, and otherwise
+   default to "prime256v1".
+ 
 +- Issue #21000: Improve the command-line interface of json.tool.
 +
  - Issue #20995: Enhance default ciphers used by the ssl module to enable
    better security an prioritize perfect forward secrecy.