exclude: Fix bug13736 - stop backup of qos perl programs

exclude: Fix bug13736 - stop backup of qos perl programs

- The exclude file only had the qos.pl file from the bin directory excluded from the
   backup. This meant that 5 other perl programs were being backed up and therefore
   any restore would overwrite new updated versions such as the makeqosscripts.pl file.
- This addition to the backup exclude file now excludes all .pl files from the qos/bin
   directory.
- This also means that any restore from earlier backups that included the other .pl files
   will not restore thosde files.
- Tested out on an IPFire physical system.

Fixes: bug13736
Tested-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>