inet: fix improper empty comparison

inet: fix improper empty comparison

BugLink: http://bugs.launchpad.net/bugs/1722702
When doing my reuseport rework I screwed up and changed a

if (hlist_empty(&tb->owners))

to

if (!hlist_empty(&tb->owners))

This is obviously bad as all of the reuseport/reuse logic was reversed,
which caused weird problems like allowing an ipv4 bind conflict if we
opened an ipv4 only socket on a port followed by an ipv6 only socket on
the same port.

Fixes: b9470c27607b ("inet: kill smallest_size and smallest_port")
Reported-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry-picked from commit fbed24bcc69d3e48c5402c371f19f5c7688871e5)
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>