unclear error in wcst_import

[Dimitar Misev]

This looks like there is some list bound checking missing, it should throw a descriptive error instead:

An error has occured in the execution of the program. Error Message: list index out of range
Stack Trace: Traceback (most recent call last):
  File "/opt/rasdaman/share/rasdaman/wcst_import/wcst_import.py", line 201, in main
    reg.run_recipe(session)
  File "/opt/rasdaman/share/rasdaman/wcst_import/master/recipe/recipe_registry.py", line 228, in run_recipe
    self.__run_recipe(session, recipe)
  File "/opt/rasdaman/share/rasdaman/wcst_import/master/recipe/recipe_registry.py", line 174, in __run_recipe
    recipe.describe()
  File "/opt/rasdaman/share/rasdaman/wcst_import/recipes/general_coverage/recipe.py", line 151, in describe
    importer = self._get_importer()
  File "/opt/rasdaman/share/rasdaman/wcst_import/recipes/general_coverage/recipe.py", line 784, in _get_importer
    coverages = self._get_coverages()
  File "/opt/rasdaman/share/rasdaman/wcst_import/recipes/general_coverage/recipe.py", line 659, in _get_coverages
    coverages = self._get_gdal_coverages(recipe_type)
  File "/opt/rasdaman/share/rasdaman/wcst_import/recipes/general_coverage/recipe.py", line 694, in _get_gdal_coverages
    self.session).to_coverages()
  File "/opt/rasdaman/share/rasdaman/wcst_import/recipes/general_coverage/abstract_to_coverage_converter.py", line 535, in to_coverages
    first_coverage_slice = coverage_slices_dict["base"][0]
IndexError: list index out of range

To reproduce see ingredients /home/ubuntu/ingestion/s2-l2a/04-60m_with_nested_overviews_level_0_1/03-ingredients_from-2018-q1-to-2020-q1//S2_L2A_32628_AOT_60m.json.