[17] update C flat api integration test

cpp/include/vereign/vereign.h

cpp/src/CMakeLists.txt

cpp/src/vereign/grpc/server.cc

cpp/src/vereign/grpc/server.hh

cpp/src/vereign/restapi/client.cc

cpp/src/vereign/restapi/client.hh

cpp/src/vereign/service/passport_service.cc

cpp/src/vereign/service/passport_service.hh

cpp/src/vereign/vereign.cc

cpp/tests/integration/CMakeLists.txt

cpp/tests/integration/init_integration_test_storage.cc

cpp/tests/integration/integration_test.cc

cpp/tests/util/env.hh

cpp/tests/vereign/grpc/server_test.cc

cpp/tests/vereign/test/device.cc

cpp/tests/vereign/test/device.hh