Use yaml.safe_dump() instead of yaml.dump()

Remove Python specific types from YAML output
Produce only basic YAML tags

Change-Id: Ib6a4c18663897efb7243ed1ff84df1c9f2abf8bf

kolla_ansible/cmd/genpwd.py

@@ -112,7 +112,7 @@ def main():
                 ])
 
     with open(passwords_file, 'w') as f:
-        f.write(yaml.dump(passwords, default_flow_style=False))
+        f.write(yaml.safe_dump(passwords, default_flow_style=False))
 
 if __name__ == '__main__':
     main()

kolla_ansible/cmd/mergepwd.py

@@ -32,7 +32,7 @@ def main():
     new_passwords.update(old_passwords)
 
     with open(args.final, "w") as destination:
-        yaml.dump(new_passwords, destination, default_flow_style=False)
+        yaml.safe_dump(new_passwords, destination, default_flow_style=False)
 
 
 if __name__ == '__main__':