[hls] Don't try to skip a stream if the offset is 0, don't raise KeyError if the m3u8 file is empty this allows the file to reload.
[hls] Don't try to skip a stream if the offset is 0, don't raise KeyError if the m3u8 file is empty this allows the file to reload.

use `!=` for `is not`

chhe/streamlink,bastimeyer/streamlink,chhe/streamlink,melmorabity/streamlink,beardypig/streamlink,gravyboat/streamlink,javiercantero/streamlink,javiercantero/streamlink,wlerin/streamlink,streamlink/streamlink,wlerin/streamlink,streamlink/streamlink,bastimeyer/streamlink,back-to/streamlink,gravyboat/streamlink,back-to/streamlink,melmorabity/streamlink,beardypig/streamlink