fixes 13346: add a variable for .dl-horizontal's offset
fixes 13346: add a variable for .dl-horizontal's offset

BS3 commits: c7cd63107b551ddb8fe201340f1fa9cbe97f8af0

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