Fix developers kubeadm installation

Waiting for kube-apiserver is failing with not finding python
executable.

Change-Id: Ib0ff95088c658fec3180f071269041faa7da2ecf
Signed-off-by: Andrii Ostapenko <andrii.ostapenko@att.com>

tools/images/kubeadm-aio/assets/entrypoint.sh

@@ -17,7 +17,7 @@ if [ "x${ACTION}" == "xgenerate-join-cmd" ]; then
 : ${TTL:="10m"}
 DISCOVERY_TOKEN="$(kubeadm token --kubeconfig /etc/kubernetes/admin.conf create --ttl ${TTL} --usages signing,authentication --groups '')"
 DISCOVERY_TOKEN_CA_HASH="$(openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | openssl dgst -sha256 -hex | sed 's/^.* /sha256:/')"
-API_SERVER=$(cat /etc/kubernetes/admin.conf | python -c "import sys, yaml; print(yaml.safe_load(sys.stdin)['clusters'][0]['cluster']['server'].split(\"//\",1).pop())")
+API_SERVER=$(cat /etc/kubernetes/admin.conf | python3 -c "import sys, yaml; print(yaml.safe_load(sys.stdin)['clusters'][0]['cluster']['server'].split(\"//\",1).pop())")
 exec echo "kubeadm join \
 --token ${DISCOVERY_TOKEN} \
 --discovery-token-ca-cert-hash ${DISCOVERY_TOKEN_CA_HASH} \

tools/images/kubeadm-aio/assets/opt/playbooks/roles/deploy-kubeadm-master/tasks/helm-cni.yaml

@@ -90,7 +90,7 @@
         dest: /etc/kubernetes/pki/calico/certs.py
 
     - name: Create yaml file
-      shell: python /etc/kubernetes/pki/calico/certs.py
+      shell: python3 /etc/kubernetes/pki/calico/certs.py
       args:
         executable: /bin/bash
         chdir: /etc/kubernetes/pki/calico

tools/images/kubeadm-aio/assets/opt/playbooks/roles/deploy-kubeadm-master/tasks/main.yaml

@@ -94,7 +94,7 @@
   delegate_to: 127.0.0.1
   block:
     - name: wait for kube api
-      shell: python /usr/bin/test-kube-api.py
+      shell: python3 /usr/bin/test-kube-api.py
       register: task_result
       until: task_result.rc == 0
       retries: 120