make umfpack work in scipy 0.14.0

kwant/solvers/sparse.py

@@ -15,10 +15,17 @@ from . import common
 
 # Note: previous code would have failed if UMFPACK was provided by scikit
 import scipy.sparse.linalg.dsolve.linsolve as linsolve
-umfpack = linsolve.umfpack
-uses_umfpack = linsolve.isUmfpack
 
 # check if we are actually using UMFPACK or rather SuperLU
+# TODO: remove the try (only using the except clause) once we depend on
+# scipy >= 0.14.0.
+try:
+	uses_umfpack = linsolve.isUmfpack
+except AttributeError:
+	uses_umfpack = linsolve.useUmfpack
+
+if uses_umfpack:
+	umfpack = linsolve.umfpack
 
 if uses_umfpack:
     # This patches a memory leak in SciPy: