Create ~/.pypirc securely (#13512).

There was a window between the write and the chmod where the user’s
password would be exposed, depending on default permissions.  Philip
Jenvey’s patch fixes it.
diff --git a/Misc/NEWS b/Misc/NEWS
index 063a6db..baea13a 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -14,6 +14,9 @@
   longer raised due to a read system call returning EINTR from within these
   methods.
 
+- Issue #13512: Create ~/.pypirc securely (CVE-2011-4944).  Initial patch by
+  Philip Jenvey, tested by Mageia and Debian.
+
 - Issue #7719: Make distutils ignore ``.nfs*`` files instead of choking later
   on.  Initial patch by SilentGhost and Jeff Ramnani.