Current scylla_setup still asks for nic even nic is already assigned in cmdline.
Fixes #3908
Signed-off-by: Amos Kong <amos@scylladb.com>
Message-Id: <6b867e17a5583c495c771a37d5fa1e8366b1d61b.1542337635.git.amos@scylladb.com>
(cherry picked from commit 09a3b11c2f)