Modify test_lzma.py to check backports.lzma
Modify test_lzma.py to check backports.lzma

This seems to work with backports.lzma under Python 3.3 (all tests pass),
but there are three (related) failures under Python 3.2 to do with error
handling:

======================================================================
ERROR: test_simple_bad_args (__main__.CompressorDecompressorTestCase)
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Traceback (most recent call last):
  File test_lzma.py, line 22, in test_simple_bad_args
    self.assertRaises(TypeError, LZMACompressor, preset=asdf)
  File /Users/peterjc/lib/python3.2/unittest/case.py, line 557, in assertRaises
    callableObj(*args, **kwargs)
SystemError: Objects/longobject.c:1197: bad argument to internal function

======================================================================
ERROR: test_bad_args (__main__.CompressDecompressFunctionTestCase)
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Traceback (most recent call last):
  File test_lzma.py, line 229, in test_bad_args
    self.assertRaises(TypeError, lzma.compress, b, preset=blah)
  File /Users/peterjc/lib/python3.2/unittest/case.py, line 557, in assertRaises
    callableObj(*args, **kwargs)
  File /Users/peterjc/lib/python3.2/site-packages/backports/lzma/__init__.py, line 432, in compress
    comp = LZMACompressor(format, check, preset, filters)
SystemError: Objects/longobject.c:1197: bad argument to internal function

======================================================================
ERROR: test_init_bad_preset (__main__.FileTestCase)
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Traceback (most recent call last):
  File test_lzma.py, line 432, in test_init_bad_preset
    LZMAFile(BytesIO(), w, preset=4.39)
  File /Users/peterjc/lib/python3.2/site-packages/backports/lzma/__init__.py, line 119, in __init__
    preset=preset, filters=filters)
SystemError: Objects/longobject.c:1197: bad argument to internal function

peterjc/backports.lzma,r3m0t/backports.lzma,peterjc/backports.lzma