Backport r62724 from trunk.  Fixes issue 2791.  subprocess.Popen.communicate
now closes its stdout and stderr fds as soon as it is finished with them.
diff --git a/Misc/NEWS b/Misc/NEWS
index 2a60b05..4eb8a80 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -82,6 +82,10 @@
 - Bug #1433694: minidom's .normalize() failed to set .nextSibling for
   last child element.
 
+- Issue #2791: subprocess.Popen.communicate explicitly closes its
+  stdout and stderr fds rather than leaving them open until the
+  instance is destroyed.
+
 
 Extension Modules
 -----------------