[DataStoreManger] Use AutoMutexLock to make code simple.
[DataStoreManger] Fix a typo of a variable name.

autoMux ->
autoMutex
[HatoholArmPluginInterface] Use AutoMutexLock to make code simple.
[HatoholArmPluginGate] Use AutoMutexLock to make code simple.
[IssueSender] Use AutoMutexLock to make code simple.
[IssueSenderManager] Use AutoMutexLock to make code simple.
Merge pull request #255 from project-hatohol/use-auto-mutex

Use auto mutex