fixed sparse.hstack, sparse.vstack to call scalar.upcast(*args), rather than scalar.upcast(args)

theano/sparse/basic.py

@@ -2302,7 +2302,7 @@ def hstack(blocks, format=None, dtype=None):
 
     blocks = [as_sparse_variable(i) for i in blocks]
     if dtype is None:
-        dtype = theano.scalar.upcast([i.dtype for i in blocks])
+        dtype = theano.scalar.upcast(*[i.dtype for i in blocks])
     return HStack(format=format, dtype=dtype)(*blocks)
 
 
@@ -2378,7 +2378,7 @@ def vstack(blocks, format=None, dtype=None):
 
     blocks = [as_sparse_variable(i) for i in blocks]
     if dtype is None:
-        dtype = theano.scalar.upcast([i.dtype for i in blocks])
+        dtype = theano.scalar.upcast(*[i.dtype for i in blocks])
     return VStack(format=format, dtype=dtype)(*blocks)