Can't import block with mod from elem

[awinogradov]

Example of bug: https://github.com/awinogradov/bem-react-core/compare/customizable...awinogradov:import?expand=1

Point: https://github.com/bem/webpack-bem-loader/blob/master/index.js#L117

How to solve:

if(main.block === ctx.block) {
  main.elem || (main.elem = ctx.elem);
}