[HatoholArmPluginInterface] HatoholArmPlugin memory leaks in cycle monitoring.

Memory leak in the function "HatoholArmPluginInterface::reply".
Resource(Sender sender) of acquired by "session.createSender()",
it must be released in "Sender.close()".
Merge pull request #838 from project-hatohol/armplugin-memory-leak

HatoholArmPlugin memory leaks in cycle monitoring.