Camera test passes even when it fails

Camera test passed even when issuing the following error:

```Traceback (most recent call last):
File "/usr/lib/python3.6/threading.py", line 916, in _bootstrap_inner
self.run()
File "/usr/lib/python3.6/threading.py", line 864, in run
self._target(*self._args, **self._kwargs)
File "/root/harmoni_catkin_ws/src/HARMONI/harmoni_sensors/harmoni_camera/nodes/camera_service.py", line 69, in start
self._read_stream_and_publish() # Start the camera service at the INIT
File "/root/harmoni_catkin_ws/src/HARMONI/harmoni_sensors/harmoni_camera/nodes/camera_service.py", line 124, in _read_stream_and_publish
raise RuntimeError("No camera frame available. Is the configured device accessible?")
RuntimeError: No camera frame available. Is the configured device accessible?```

Start with harmoni_sensors/harmoni_camera/nodes/camera_service.py, especially start and _read_stream_and_publish around the reported RuntimeError. Trace how the camera test records success and how exceptions from the service thread are handled. Done means the test does not pass when no camera frame is available.

Written by the indexing model from the issue text.