bug regarding new scalar shared variable

The extract_constant function was not aware of the new scalar shared variable and hence it did not do the right changes in that case.

bug regarding new scalar shared variable
babdf02d · Razvan Pascanu · fb69df0c · babdf02d
--- a/theano/tensor/basic.py
+++ b/theano/tensor/basic.py
@@ -2866,7 +2866,8 @@ def extract_constant(x):
        x = get_constant_value(x)
    except Exception:
        pass
-    if isinstance(x, scal.ScalarVariable):
+    if (isinstance(x, scal.ScalarVariable) or
+        isinstance(x, scal.sharedvar.ScalarSharedVariable)):
        if x.owner and isinstance(x.owner.op, ScalarFromTensor):
            x = x.owner.inputs[0]
        else: