Previously, some interfaces in the client ifname list have been kept.
The actual reason for this is unknown, it might have been used for the
bat0 interfaces.
Filtering the interface list in this way might lead to interfaces being
retained unintentionally, especially with the diverse naming of DSA
interfaces.
As it is not required anymore, remove the retention of some interfaces
completely.
Fixes: #207
Signed-off-by: Fabian Bläse <fabian@blaese.de>