Revert "h264parse: expose compatible profiles to downstream"

This reverts commit 3910cbe7ce1a67ed5506f87e4c5a005c168d0e6c.
mirror: Needs remap when the mode changes.

This caused the user to think the mode wasn't taken into account.
dashdemux: Find current segment in the streams that have just been setup

Using demux->streams will just skip the whole loop as demux->streams will
always be NULL at that point

https://bugzilla.gnome.org/show_bug.cgi?id=741285