ipsec-interfaces: Fixes bug12763

ipsec-interfaces: Fixes bug12763

- Some of the ip route commands are not redirected to null. This causes the "FIB table does
   not exist" message from bug12763
- This patch makes all ip route commands get redirected to null, preventing the error
   message from being seen at boot.
- One of the ip rule commands is not redirected to null. This causes the "RTNETLINK
    answers: no such file or directory" message.
- This patch makes all ip rule commands get redirected to null, preventing the error
   message from being seen at boot.
- Additional patches in this set ensure that all ip route and ip rule commands in all
   IPFire code is redirected to null unless the output of the ip route or ip rule command
   is used in a variable for use elsewhere in the code.
- Tested on my vm system and confirmed that the fix in ipsec-interfaces stops the "FIB
   table does not exist" and "RTNETLINK answers: no such file or directory" messages during
   boot.

Fixes: Bug#12763
Tested-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Arne Fitzenreiter <arne_f@ipfire.org>