Cleanup machine based on the state in configuration file for mini installer test.

chrome/test/mini_installer/variable_expander.py

Index: chrome/test/mini_installer/variable_expander.py
diff --git a/chrome/test/mini_installer/variable_expander.py b/chrome/test/mini_installer/variable_expander.py
index 551bf61b21b445e55f8fadea0ee347eab5ffb6f7..807c6f99acdb14a3beb2dec7a773807c86e5f789 100644
--- a/chrome/test/mini_installer/variable_expander.py
+++ b/chrome/test/mini_installer/variable_expander.py
@@ -164,7 +164,7 @@ class VariableExpander:
                      mini_installer_product_name)
 
 
-  def Expand(self, str):
+  def Expand(self, input_string):
     """Expands variables in the given string.
 
     This method resolves only variables defined in the constructor. It does not
@@ -173,9 +173,9 @@ class VariableExpander:
     be raised.
 
     Args:
-      str: A string.
+      input_string: A string with variables.
 
     Returns:
       A new string created by replacing variables with their values.
     """
-    return string.Template(str).substitute(self._variable_mapping)
+    return string.Template(input_string).substitute(self._variable_mapping)