Revert "mkv: a subchapter with no end timestamp cannot match the chapter looked for"
Revert "mkv: a subchapter with no end timestamp cannot match the chapter looked for"

This reverts commit 8dd38a675a018911e1000bf95ed9f8bdde4f9350.

We want stricter rules for which chapter holds the timestamp

Signed-off-by: Jean-Baptiste Kempf <7b85a41a628204b76aba4326273a3ccc74bd009a@videolan.org>

xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc