[issue14061] Misc fixes and cleanups in archiving code in shutil and test_shutil

[Serhiy Storchaka]

Changes by Serhiy Storchaka <storchaka at gmail.com>:


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nosy: +serhiy.storchaka
type:  -> behavior
versions: +Python 3.4, Python 3.5 -Python 3.2, Python 3.3

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<http://bugs.python.org/issue14061>
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