6rd : remove 6rd tunnel delete workaround
Remove 6rd tunnel delete workaround in as the real issue
is now solved in netifd
(https://git.openwrt.org/?p=project/netifd.git;a=commit;h=8f82742ca4f47f459284f3a07323d04da72ea5f6)
Signed-off-by: Hans Dedecker <[email protected]>