C++ review fixes

include/object.h

include/scoped_guard.h

src/CMakeLists.txt

src/box/bitset_index.cc

src/box/box_lua.cc

src/box/hash_index.cc

src/coeio.cc

src/coio.cc

src/exception.cc

src/iproto.cc

src/log_io.cc

src/lua/lua_socket.cc

src/memcached.cc

src/recovery.cc

src/scoped_guard.cc