Otherwise, the Create/Destroy sequence crashes.

It previously assumed TRUSTED.
No functionnal/security changes in this commit.

 This will force people to use VLC_INPUT_OPTION_TRUSTED flag when they
need it and ease security review.
 This commit has no functionnal/security changes.

This reverts commit 74d68fbd.

Default duration of 10s when fake isn't forced. Make it possible to use fake:///path/to/image as well.

Signed-off-by: Antoine Cellerier <dionoea@videolan.org>

Without this I needed to give --dvb-srate=6875000 to vlc with
channels.conf file for it to work proberly, please review that it
doesn't cause any funky issues to other than dvb-c stuff.

The caller is going to call poll() or something, so locking a mutex is
surely not a performance issue.

Signed-off-by: Laurent Aimar <fenrir@videolan.org>