Log on read and write errors

std::read and std::write can fail, returning -1.

In such case log the error. It should be propagated to upper layers, but
there is evident way. EAGAIN and EINT should also be handled.

Signed-off-by: Kevin Rocard <kevinx.rocard@intel.com>
Log on pthread_join failure

pthread_join may fail, such error was not detected.

Log if such case hapends and fail RemoteProcessorServer::start.

Signed-off-by: Kevin Rocard <kevinx.rocard@intel.com>