Stop using platform-python

Since python2 is not supported long time - there's
no need to use /usr/libexec/platform-python.
Also for supporting Debian/Ubuntu - we need to
change that to /usr/bin/python3.

Change-Id: I0d477325e0edd13d1aba211c13dc2e8b7a9b4c98

ansible/dnf.yml

@@ -2,7 +2,7 @@
 - name: Ensure DNF repos are configured
   hosts: seed-hypervisor:seed:overcloud
   vars:
-    ansible_python_interpreter: /usr/libexec/platform-python
+    ansible_python_interpreter: /usr/bin/python3
   tags:
     - dnf
   tasks:

ansible/kayobe-ansible-user.yml

@@ -43,7 +43,7 @@
     ansible_user: "{{ bootstrap_user }}"
     # We can't assume that a virtualenv exists at this point, so use the system
     # python interpreter.
-    ansible_python_interpreter: /usr/libexec/platform-python
+    ansible_python_interpreter: /usr/bin/python3
   roles:
     - role: singleplatform-eng.users
       users:
@@ -70,7 +70,7 @@
   vars:
     # We can't assume that a virtualenv exists at this point, so use the system
     # python interpreter.
-    ansible_python_interpreter: /usr/libexec/platform-python
+    ansible_python_interpreter: /usr/bin/python3
   tasks:
     - name: Verify that a command can be executed
       command: hostname

ansible/kayobe-target-venv.yml

@@ -69,7 +69,7 @@
       vars:
         # Use the system python interpreter since the virtualenv might not
         # exist.
-        ansible_python_interpreter: /usr/libexec/platform-python
+        ansible_python_interpreter: /usr/bin/python3
       when: virtualenv is defined
 
     # If we gathered facts earlier it would have been with a different Python

ansible/kolla-pip.yml

@@ -15,7 +15,7 @@
     hosts_in_kolla_inventory: >-
       {{ kolla_overcloud_inventory_top_level_group_map.values() |
          map(attribute='groups') | flatten | unique | union(['seed']) | join(':') }}
-    ansible_python_interpreter: /usr/libexec/platform-python
+    ansible_python_interpreter: /usr/bin/python3
   tasks:
     - import_role:
         name: pip

ansible/pip.yml

@@ -4,7 +4,7 @@
   tags:
     - pip
   vars:
-    ansible_python_interpreter: /usr/libexec/platform-python
+    ansible_python_interpreter: /usr/bin/python3
   roles:
     - role: pip
   gather_facts: false