The second amendment does not say we have a right. It says the right shall not be taken away.
All rights are assumed, unless explicitly mentioned as falling under the category of "not a right".
If you will indulge an old fool for a moment.
I'm quite sure that those who wrote the Constitution were intelligent enough to know that you can't take away something that didn't exist. Therefore, I think I can safely assume that they believed that the right of Habeas Corpus did exist and therefore it was their intent to protect that right.
How can one take away my cloak when I do not have a cloak? To assume that one could take away from me something I did not have is just plain stupidity.