Add gce grain to salt config, change apiserver salt config.

cluster/templates/salt-master.sh

@@ -25,6 +25,7 @@ cat <<EOF >/etc/salt/minion.d/grains.conf
 grains:
   roles:
     - kubernetes-master
+  cloud: gce
 EOF
 
 # Auto accept all keys from minions that try to join

cluster/templates/salt-minion.sh

@@ -31,6 +31,7 @@ grains:
   roles:
     - kubernetes-pool
   cbr-cidr: $MINION_IP_RANGE
+  cloud: gce
 EOF
 
 # Install Salt