fix assertReducerShape

[jeno5980515]

Hi, I remove the part that you check the private namespace is used or not.

I think the code is no use for the condition.
If the namespace is used, the reducer should return a initial state instead of undefined.
Otherwise if it really return undefined it should block at the previous error.
Only check is undefined or not is not working for check the private namespace is used or not.

I think it should check the initial state and the state return from the reducer which give private namespace action are deep different or not.
However it will reduce lot's performance I think.

Thanks!

[timdorr]

This was added in #259 to fix #186. This is correct as-is and should not be removed.

[jeno5980515]

I had read the reference you give.
However, I think the check code still not throw any error if I give a reducer with handle the action with @@redux/INIT or @@INIT.
By the way if the reducer return undefined, it should throw error at the
initialState === 'undefined'
not at
typeof reducer(undefined, { type }) === 'undefined'

Thanks!