`make-col-ready()`: remove the unused `$gutter` variable (#34334)
`make-col-ready()`: remove the unused `$gutter` variable (#34334)

Co-authored-by: XhmikosR <b60f67e10123951b393d9ba15dcf79efc14744bb@gmail.com>
Co-authored-by: Mark Otto <12d1534cbab533fa770a644b94441a210fc71171@gmail.com>
tjkohli/bootstrap,inway/bootstrap,m5o/bootstrap,twbs/bootstrap,tjkohli/bootstrap,coliff/bootstrap,coliff/bootstrap,inway/bootstrap,m5o/bootstrap,twbs/bootstrap,inway/bootstrap