livehttp: don't remove previous playlist on open if segment-number is given
livehttp: don't remove previous playlist on open if segment-number is given

If we provide initial segment-number, most likely we want to continue
where we have left of, so leave old playlist-file there and just
overwrite it when we updated it.

default initial-segment-number is 1 so don't test against 0

krichter722/vlc,shyamalschandra/vlc,vlc-mirror/vlc,vlc-mirror/vlc,shyamalschandra/vlc,shyamalschandra/vlc,vlc-mirror/vlc,krichter722/vlc,vlc-mirror/vlc,shyamalschandra/vlc,xkfz007/vlc,xkfz007/vlc,krichter722/vlc,xkfz007/vlc,krichter722/vlc,krichter722/vlc,shyamalschandra/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,shyamalschandra/vlc,vlc-mirror/vlc,krichter722/vlc,shyamalschandra/vlc,vlc-mirror/vlc,xkfz007/vlc,krichter722/vlc,vlc-mirror/vlc