get dictionary of loc_type: loc_file, .loc files in the galaxy base
    for example: {"bwa": "/galaxy_base_path/tool-dir/bwa_index.loc"}

def get_loc_files(galaxy_base):
    """
    get dictionary of loc_type: loc_file, .loc files in the galaxy base
    for example: {"bwa": "/galaxy_base_path/tool-dir/bwa_index.loc"}
    """
    return {k: os.path.join(galaxy_base, "tool-data", v) for k, v in REF_FILES.items()}