Bug #1550714: fix SystemError from itertools.tee on negative value for n.

Needs backport to 2.5.1 and earlier.
diff --git a/Misc/NEWS b/Misc/NEWS
index fe3ed79..794ccc1 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -27,6 +27,8 @@
 
 - Bug #1548092: fix curses.tparm seg fault on invalid input.
 
+- Bug #1550714: fix SystemError from itertools.tee on negative value for n.
+
 
 Tests
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