(Merge 3.1) Issue #12012: ssl.PROTOCOL_SSLv2 becomes optional

OpenSSL is now compiled with OPENSSL_NO_SSL2 defined (without the SSLv2
protocol) on Debian: fix the ssl module on Debian Testing and Debian Sid.

Optimize also ssl.get_protocol_name(): speed does matter!
diff --git a/Misc/NEWS b/Misc/NEWS
index 4a4767e..4309858 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -618,6 +618,8 @@
 Library
 -------
 
+- Issue #12012: ssl.PROTOCOL_SSLv2 becomes optional.
+
 - Issue #10916: mmap should not segfault when a file is mapped using 0 as length
   and a non-zero offset, and an attempt to read past the end of file is made
   (IndexError is raised instead).  Patch by Ross Lagerwall.