ping: always initialize ->sin6_scope_id and ->sin6_flowinfo

[net-next commit c26d6b46da3ee86fa8a864347331e5513ca84c2b]

If we don't need scope id, we should initialize it to zero.
Same for ->sin6_flowinfo.

Change-Id: I74764edf3d0567f5ae094b2e83484cdfe05f6098
Cc: Lorenzo Colitti <lorenzo@google.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Acked-by: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>