bug#22738: Build failure in vigra

[Danny Milosavljevic]

/tmp/guix-build-vigra-1.10.0.drv-0/build
...
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ERROR: test_arraytypes.testMethods
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Traceback (most recent call last):
  File 
"/gnu/store/m71dy36xl5jcp1qgw9dkyab3yv9gpibx-python2-nose-1.3.7/lib/python2.7/site-packages/nose-1.3.7-py2.7.egg/nose/case.py",
 line 197, in runTest
    self.test(*self.arg)
  File 
"/tmp/guix-build-vigra-1.10.0.drv-0/build/vigranumpy/test/test_arraytypes.py", 
line 1331, in testMethods
    nz = n.nonzero()
  File 
"/tmp/guix-build-vigra-1.10.0.drv-0/build/vigranumpy/vigra/arraytypes.py", line 
1285, in nonzero
    res[k].axistags = AxisTags(AxisInfo(self.axistags[k]))
AttributeError: 'numpy.ndarray' object has no attribute 'axistags'

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