Allow netd to use NETLINK_SOCK_DIAG.

This is needed to kill sockets using the new SOCK_DESTROY
operation instead of using SIOCKILLADDR.

Bug: 26976388

(cherry picked from commit b38e2790)

Change-Id: Id80c6278f19f9fd20fe8d4fca72f84bff9249ed8

netd.te

@@ -18,6 +18,7 @@ allow netd self:netlink_kobject_uevent_socket create_socket_perms;
 allow netd self:netlink_route_socket nlmsg_write;
 allow netd self:netlink_nflog_socket create_socket_perms;
 allow netd self:netlink_socket create_socket_perms;
+allow netd self:netlink_tcpdiag_socket { create_socket_perms nlmsg_read nlmsg_write };
 allow netd shell_exec:file rx_file_perms;
 allow netd system_file:file x_file_perms;
 allow netd devpts:chr_file rw_file_perms;