#7 fix handling of -n parameter

[Dirk Jagdmann]

Although dvbstream accepts the -n parameter on the
command line to set the number of seconds to record, it
does not handle the value set, or in other words does
not stop recording after the elapsed time.

This patch fixes this bug and dvbstream will cleanly
stop recording after the number of seconds set with -n
have elapsed.

[Dirk Jagdmann]

fix -n parameter handling