[Bug #1542016] Report PCALL_POP value.  This makes the return value of sys.callstats() match its docstring.

Backport candidate.  Though it's an API change, this is a pretty obscure
portion of the API.
diff --git a/Misc/NEWS b/Misc/NEWS
index c79a55a..a1033bf 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -14,6 +14,9 @@
 
 - Patch #1549049: Support long values in structmember.
 
+- Bug #1542016: make sys.callstats() match its docstring and return an
+  11-tuple (only relevant when Python is compiled with -DCALL_PROFILE).
+
 - Bug #1545497: when given an explicit base, int() did ignore NULs
   embedded in the string to convert.