lxd/instance: Use project aware inst.LogPath() function when clearing log dir in instanceCreateInternal
lxd/instance: Use project aware inst.LogPath() function when clearing log dir in instanceCreateInternal

Avoids clearing lxc.conf of a different container and preventing access to it.

Signed-off-by: Thomas Parrott <6b778ce645fb0e3dde76d79eccad490955b1ae74@canonical.com>

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