Revert "post_deploy: support python3 for undercloud scripts."

This reverts commit 1143714b34.

So we're actually changing this out in packaging. It'll fail
if you deploy from code, but the fedora version of the 
package should end up with /usr/bin/python3. This is why
we didn't hit this in CI.

https://review.rdoproject.org/r/#/c/18465/

Change-Id: Ibad6ff84b33ae3d6011c87028fe02695eea69482

extraconfig/post_deploy/clouds_yaml.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env $PYTHON
+#!/usr/bin/env python
 import os
 import yaml
 

extraconfig/post_deploy/standalone_post.yaml

@@ -98,12 +98,7 @@ resources:
         - name: region_name
         - name: user_name
         - name: user_domain_name
-      config:
-        str_replace:
-          template:
-            {get_file: ./clouds_yaml.py}
-          params:
-            $PYTHON: {get_param: PythonInterpreter}
+      config: {get_file: ./clouds_yaml.py}
 
   CloudsYamlDeployment:
     type: OS::Heat::SoftwareDeployments

extraconfig/post_deploy/undercloud_ctlplane_network.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env $PYTHON
+#!/usr/bin/env python
 
 import json
 import netaddr

extraconfig/post_deploy/undercloud_post.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env $PYTHON
+#!/usr/bin/env python
 
 import json
 import os

extraconfig/post_deploy/undercloud_post.yaml

@@ -75,10 +75,6 @@ parameters:
     type: string
     default: 'undercloud'
     description: Cloud name for the clouds.yaml
-  PythonInterpreter:
-    type: string
-    description: The python interpreter to use for python and ansible actions
-    default: /usr/bin/python
 
 conditions:
 
@@ -160,12 +156,7 @@ resources:
         - name: region_name
         - name: user_name
         - name: user_domain_name
-      config:
-        str_replace:
-          template:
-            {get_file: ./clouds_yaml.py}
-          params:
-            $PYTHON: {get_param: PythonInterpreter}
+      config: {get_file: ./clouds_yaml.py}
 
   CloudsYamlDeployment:
     type: OS::Heat::SoftwareDeployments
@@ -203,12 +194,7 @@ resources:
       group: script
       inputs:
         - name: config
-      config:
-        str_replace:
-          template:
-            {get_file: ./undercloud_post.py}
-          params:
-            $PYTHON: {get_param: PythonInterpreter}
+      config: {get_file: ./undercloud_post.py}
 
   UndercloudPostPyDeployment:
     type: OS::Heat::SoftwareDeployments
@@ -234,12 +220,7 @@ resources:
       group: script
       inputs:
         - name: config
-      config:
-        str_replace:
-          template:
-            {get_file: ./undercloud_ctlplane_network.py}
-          params:
-            $PYTHON: {get_param: PythonInterpreter}
+      config: {get_file: ./undercloud_ctlplane_network.py}
 
   UndercloudCtlplaneNetworkDeployment:
     type: OS::Heat::SoftwareDeployments