fix: [docker-host] remove warning about ``/etc/default/lxc`` not existent

precise/host/hooks/install.d/70-0k.sh

@@ -103,6 +103,7 @@ apt-get install -y kal-shlib-charm </dev/null
     git pull -r &&
     ln -sfn /opt/apps/lxc-scripts/bin/lxc-* /usr/local/sbin/ &&
 
+    if [ -f /etc/default/lxc ]; then
         if [ -f /etc/default/lxc.pre-install ]; then
             cp /etc/default/lxc.pre-install /etc/default/lxc
         else
@@ -116,6 +117,7 @@ apt-get install -y kal-shlib-charm </dev/null
             ln -sfn /opt/apps/lxc-scripts/usr/lib/lxc/templates/lxc-0k-ubuntu-cloud /usr/share/lxc/templates
             echo TEMPLATE_PATH=/usr/share/lxc/templates >> /etc/default/lxc
         }
+    fi
 )
 
 ##