core: Let PS3 seek into unseekable
core: Let PS3 seek into unseekable

If PS3 wants to send a (totally unneeded) seek request for a resource that
is not seekable, let it!

GNOME/rygel,luisbg/rygel,Pelagicore/Media-Manager-Rygel-patched,Tarnyko/rygel,Tarnyko/rygel,Pelagicore/Media-Manager-Rygel-patched,Pelagicore/Media-Manager-Rygel-patched,jku/rygel,jku/rygel,GNOME/rygel,GNOME/rygel