net: Enable a userns root rtnl calls that are safe for unprivilged users

- Only allow moving network devices to network namespaces you have
  CAP_NET_ADMIN privileges over.

- Enable creating/deleting/modifying interfaces
- Enable adding/deleting addresses
- Enable adding/setting/deleting neighbour entries
- Enable adding/removing routes
- Enable adding/removing fib rules
- Enable setting the forwarding state
- Enable adding/removing ipv6 address labels
- Enable setting bridge parameter

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_netlink.c

@@ -240,9 +240,6 @@ int br_setlink(struct net_device *dev, struct nlmsghdr *nlh)
 	struct nlattr *tb[IFLA_BRPORT_MAX];
 	int err;
 
-	if (!capable(CAP_NET_ADMIN))
-		return -EPERM;
-
 	ifm = nlmsg_data(nlh);
 
 	protinfo = nlmsg_find_attr(nlh, sizeof(*ifm), IFLA_PROTINFO);