[3.7] bpo-33031: Remove dead code in C implementation of OrderedDict. (GH-6120) (GH-6433)

This code doesn't have effect on the final result, but causes
GCC 8 warnings and can have an undefined behavior.
(cherry picked from commit 827d49f3cf0296f1e267eae6834a977cf312cc1e)
1 file changed