Use "with" keyword to open & close file.

slapos/recipe/agent/__init__.py

@@ -84,7 +84,7 @@ class Recipe(BaseSlapRecipe, GenericSlapRecipe):
     configuration.write(open(configuration_path, "w"))
 
     agent_crond_path = os.path.join(crond, "agent")
-    agent_crond = open(agent_crond_path, "w")
+    with open(agent_crond_path, "w") as agent_crond:
       agent_crond.write("*/5 * * * * %s -S %s --pidfile=%s %s\n" % (
           self.options["python_binary"],
           self.options["agent_binary"],
@@ -101,7 +101,6 @@ class Recipe(BaseSlapRecipe, GenericSlapRecipe):
         self.options["report_stop"],
         configuration_path,
       ))
-    agent_crond.close()
 
     return self.path_list + [configuration_path, key_filepath, cert_filepath, agent_crond_path]