proposed fix for #796

Well, I removed currentRows and recordKey everywhere because I dind't find what are they meant to do.
Removing lines 164 to 169 is what fixes this problem.
I've tried it with the original error data and it works fine now.
@tfmorris:
I tried to run the test  https://github.com/tfmorris/OpenRefine/commit/2c0cb0d65700d48a68dbeec18103e1c4e71fbbe6
but it doesn't work, about this:
line 143 to 145: apparently project.rows.get(0).cells.get(1) and get(2) are allways null, I don't know why and also, when the last(s) cells of a column are empty, they are not stores, this leads to 143 to match with to be successful (it has cells 1 and 2 extra and 2 less at the end so, equilibrium) and 144 and 145 to complain saying that they have more cells than expected
line 147: "data1"? where does this come from, I think that should be "1" and for 148 and 149 have in mind last item