lxd/instance/qemu: Set msize on 9p
lxd/instance/qemu: Set msize on 9p

This sets a 1M msize for the config 9p mount and 32MB msize for normal
disk mounts. This hides the QEMU warning and should provide better
performance when using 9p.

Closes #10219

Signed-off-by: Stéphane Graber <089afc6d81f66f1168a9849e15660feae286e024@ubuntu.com>

hallyn/lxd,hallyn/lxd,stgraber/lxd,stgraber/lxd,lxc/lxd,lxc/lxd,stgraber/lxd,stgraber/lxd,stgraber/lxd,lxc/lxd,hallyn/lxd,lxc/lxd,stgraber/lxd,hallyn/lxd,hallyn/lxd,lxc/lxd,lxc/lxd,hallyn/lxd,lxc/lxd,stgraber/lxd