lxd/instance/drivers: Don't overwrite template triggers
lxd/instance/drivers: Don't overwrite template triggers

Fixes #8674

Signed-off-by: Fergus Dall <7ccc9f4990837cdc742a523b6780556a7c5e07d8@google.com>

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