Change python interpreter

There is inconsistent use of either `/usr/bin/python` or
`/usr/bin/env python`. This makes for unexpected results when a
user might be using a virtualenv.

Change-Id: Ibb030f920a8869f9113ade70b66a921cc815060d

ansible/action_plugins/merge_configs.py

-#!/usr/bin/python
+#!/usr/bin/env python
 
 # Copyright 2015 Sam Yaple
 # Copyright 2017 99Cloud Inc.

ansible/action_plugins/merge_yaml.py

-#!/usr/bin/python
+#!/usr/bin/env python
 
 # Copyright 2015 Sam Yaple
 # Copyright 2016 intel

ansible/library/bslurp.py

-#!/usr/bin/python
+#!/usr/bin/env python
 
 # Copyright 2015 Sam Yaple
 #

ansible/library/kolla_docker.py

-#!/usr/bin/python
+#!/usr/bin/env python
 
 # Copyright 2015 Sam Yaple
 #

ansible/library/kolla_toolbox.py

-#!/usr/bin/python
+#!/usr/bin/env python
 
 # Copyright 2016 99cloud Inc.
 #

ansible/library/merge_configs.py

-#!/usr/bin/python
+#!/usr/bin/env python
 
 # Copyright 2015 Sam Yaple
 #

ansible/library/merge_yaml.py

-#!/usr/bin/python
+#!/usr/bin/env python
 
 # Copyright 2015 Sam Yaple
 # Copyright 2016 intel

ansible/roles/keystone/files/fernet_rotate_cron_generator.py

-#!/usr/bin/python
+#!/usr/bin/env python
 
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.

tests/test_kolla_docker.py

-#!/usr/bin/python
+#!/usr/bin/env python
 
 # Copyright 2016 NEC Corporation
 # Licensed under the Apache License, Version 2.0 (the "License");

tests/test_merge_config.py

-#!/usr/bin/python
+#!/usr/bin/env python
 
 # Copyright 2016 99cloud Inc.
 # Licensed under the Apache License, Version 2.0 (the "License");

tools/validate-all-file.py

-#!/usr/bin/python
+#!/usr/bin/env python
 
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.

tools/validate-yaml.py

-#!/usr/bin/python
+#!/usr/bin/env python
 
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.