hls.js: remove useless code, improve readability of seek() method
hls.js: remove useless code, improve readability of seek() method

flavioribeiro/clappr,jfairley/clappr,clappr/clappr,flavioribeiro/clappr,dayvson/clappr,dayvson/clappr,dayvson/clappr,clappr/clappr,flavioribeiro/clappr,jfairley/clappr,clappr/clappr,jfairley/clappr