Parsed and used the length_field() of the PMT message instead of using
the length field of the message struct, which does not seem to be filled
correctly by e.g. MythTV.
Signed-off-by: NHenrik Kurelid <henrik@kurelid.se>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>