Code review comment for lp://staging/~thomas-voss/media-hub/switch-to-properties-cpp

I was a bit hasty approving last time, I discovered a compile issue:

/home/phablet/switch-to-properties-cpp/tests/acceptance-tests/service.cpp:45:39: error: narrowing conversion of ‘((& ms)->std::chrono::duration<_Rep, _Period>::count<long long int, std::ratio<1ll, 1000ll> >() * 1000000ll)’ from ‘std::chrono::duration<long long int, std::ratio<1ll, 1000ll> >::rep {aka long long int}’ to ‘__syscall_slong_t {aka long int}’ inside { } [-Werror=narrowing]
     timespec ts{ 0, ms.count() * 1000 * 1000};