fixed cula runtime error (libcula.so not found)

theano/sandbox/cuda/cula.py

@@ -16,7 +16,7 @@ cula_available = False
 try:
     from scikits.cuda import cula
     cula_available = True
-except (ImportError, OSError, pkg_resources.DistributionNotFound):
+except (ImportError, OSError, RuntimeError, pkg_resources.DistributionNotFound):
     pass
 
 cula_initialized = False