TIling: When the scan fail a reconstruction is still requested

This have to be checked, it's maybe wrong.

Here is the log from the tomovis service.

But daiquiri tomo server but probably be fixed.

Traceback (most recent call last):
  File "/users/blissadm/conda/miniconda/envs/tomovis/lib/python3.7/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/users/blissadm/conda/miniconda/envs/tomovis/lib/python3.7/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/users/blissadm/local/tomovis.git/tomovis/process/image_tiling.py", line 299, in <module>
    reader = TilingScanReader(options.input_filename, options.input_scan)
  File "/users/blissadm/local/ebs-tomo.git/tomo/helpers/tiling_reader.py", line 147, in __init__
    self.__front_tiling_group = self.__h5[path_from_id(3)]
  File "/users/blissadm/local/ebs-tomo.git/tomo/helpers/tiling_reader.py", line 141, in path_from_id
    scan_number = scan_numbers[index]
  File "h5py/_objects.pyx", line 54, in h5py._objects.with_phil.wrapper
  File "h5py/_objects.pyx", line 55, in h5py._objects.with_phil.wrapper
  File "/users/blissadm/conda/miniconda/envs/tomovis/lib/python3.7/site-packages/h5py/_hl/dataset.py", line 710, in __getitem__
    return self._fast_reader.read(args)
  File "h5py/_selector.pyx", line 351, in h5py._selector.Reader.read
  File "h5py/_selector.pyx", line 151, in h5py._selector.Selector.apply_args
IndexError: Index (3) out of range for (0-2)