[CVE-2016-5243] fix an infoleak in tipc

[Luis Henriques]

Following this email I'm sending the CVE-2016-5243 fix backports for all
series < Xenial.  The following changes were required in the backports:

- modify function tipc_node_get_links (net/tipc/node.c) instead of
  tipc_nl_compat_link_dump (net/tipc/netlink_compat.c).  This function was
  moved with commit 357ebdbfca0b ("tipc: convert legacy nl link dump to nl
  compat")

- use strncpy() instead of nla_strlcpy() as the later isn't applicable
  before commit 357ebdbfca0b

I'll also send the (clean cherry-pick) fix for xenial, but the upstream
patch has an issue that is not present in these backports, so it 2 patches
are required for this kernel.