sentinel_2pc → sentinel Relation

File in src/uhs/twophase/sentinel_2pc	Includes file in src/uhs/sentinel
uhs/twophase/sentinel_2pc/controller.hpp	async_interface.hpp
uhs/twophase/sentinel_2pc/controller.hpp	uhs/sentinel/client.hpp
uhs/twophase/sentinel_2pc/controller.hpp	uhs/sentinel/format.hpp
uhs/twophase/sentinel_2pc/server.hpp	async_interface.hpp