rm redundant ampersands from button-groups LESS
rm redundant ampersands from button-groups LESS

BS3 commit fa3959a1e10da848867be73ac1d18d209367a9b0

mozillo/todc-bootstrap,todc/todc-bootstrap,aaroncnhk/todc-bootstrap,2947721120/todc-bootstrap,todc/todc-bootstrap,ztx1491/todc-bootstrap,todc/todc-bootstrap,up2vs/todc-bootstrap,2947721120/googlebt4