Address standalone kubelet config case

Also place in global vars and do not repeat the kube_*_config_dir
and kube_namespace vars for better code maintainability and UX.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

roles/kubernetes/node/templates/rh-kubelet.initd.j2

@@ -27,7 +27,7 @@ pidfile="/var/run/$prog.pid"
 lockfile="/var/lock/subsys/$prog"
 logfile="/var/log/$prog"
 
-[ -e /etc/kubernetes/$prog.env ] && . /etc/kubernetes/$prog.env
+[ -e {{kube_config_dir}}/$prog.env ] && . {{kube_config_dir}}/$prog.env
 
 start() {
     if [ ! -x $exec ]; then
@@ -35,7 +35,7 @@ start() {
         echo "Docker executable $exec not found"
       else
         echo "You do not have permission to execute the Docker executable $exec"
-      fi	      
+      fi
       exit 5
     fi