attacg: shut up gcc
attacg: shut up gcc

Invalid warning but let's please the compiler.

Closes lxc#2885.

Signed-off-by: tomponline <311bb6b467675b937a24a1860d8fd7780626c535@tomp.uk>

ss1h2a3tw/lxc,hallyn/lxc,hallyn/lxc,hallyn/lxc,ss1h2a3tw/lxc,ss1h2a3tw/lxc