EC.local_data() can't handle extensions of number fields

[arminstraub]

In 4.4.4 the following code produces a ValueError?:

sage: K.<a> = NumberField(x^2+1)
sage: L.<b> = K.extension(x^2-17)
sage: E = EllipticCurve(L, [1,1])
sage: E.local_data()

As a workaround, one can use absolute_field:

L1.<c> = L.absolute_field()
E1 = EllipticCurve(L1, [1,1])
E1.local_data()