Added license comment to each objectstore source file

objectstore/Action.hpp

objectstore/AdminUsersList.cpp

objectstore/AdminUsersList.hpp

objectstore/Agent.cpp

objectstore/Agent.hpp

objectstore/AgentRegister.cpp

objectstore/AgentRegister.hpp

objectstore/AgentVisitor.hpp

objectstore/AgentWatchdog.cpp

objectstore/AgentWatchdog.hpp

objectstore/Backend.hpp

objectstore/BackendRados.cpp

objectstore/BackendRados.hpp

objectstore/BackendTest.cpp

objectstore/BackendTest.hpp

objectstore/BackendVFS.cpp

objectstore/BackendVFS.hpp

objectstore/Counter.hpp

objectstore/FIFO.cpp

objectstore/FIFO.hpp