[HatoholArmPluginGate] Fix a build error.

The following error happens on Ubuntu 14.04 and with the --enable-cpp11 option.

HatoholArmPluginGate.cc: In member function 'void HatoholArmPluginGate::cmdHandlerSendArmInfo(const HapiCommandHeader*)':
HatoholArmPluginGate.cc:597:45: error: 'typeof' was not declared in this scope
  armInfo.stat    = LtoN((typeof(armInfo.stat))body->stat);