[MDL] Chip variables erased

[BastienBnd]

Current behaviour

At the end of the material-design-lite/src/_variables.scss file there is a "FOCUS OVERRIDE" message and some new mdl variables about chips are missing:
$chip-bg-color: rgb(222, 222, 222) !default;
$chip-bg-active-color: rgb(214, 214, 214) !default;
$chip-height: 32px !default;
$chip-font-size: 13px !default;

Expected behaviour

We had like to have these variables defined in order to use mdl chips.

Versions

Focus-core: 2.1.1
Focus-components: 2.1.4