Backport r67974:

#4759: allow None as first argument of bytearray.translate(), for consistency with bytes.translate().

Also fix segfault for bytearray.translate(x, None) -- will backport this part to 3.0 and 2.6.
diff --git a/Misc/NEWS b/Misc/NEWS
index 3fc5664..e60e02a 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@
 Core and Builtins
 -----------------
 
+- Issue #4759: None is now allowed as the first argument of
+  bytearray.translate().  It was always allowed for bytes.translate().
+
 - Added test case to ensure attempts to read from a file opened for writing
   fail.