[py3.3] bz2: disallow pickling for compressor/decompressor (cpython compat)

Merged Bitbucket Importer requested to merge bitbucket/merged-pr-268 into branch/py3.3

Created originally on Bitbucket by numerodix (Martin Matusiak)

Was already merged in Bitbucket before import, marked as merged by the import user

Fixes test failures in bz2: http://buildbot.pypy.org/summary/longrepr?testname=unmodified&builder=pypy-c-app-level-linux-x86-64&build=2412&mod=lib-python.3.test.test_bz2

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