Drop .controls-row for grid inputs.
Given input elements in 3.0 are set to width: 100% by default, and since we don't want to implement a separate input grid, we've opted to drop the .controls-row functionality.
Instead, folks should wrap inputs in standard grid markup: with a wrapping .row and individual .span* columns around each input.

See https://github.com/twbs/bootstrap/pull/6342