Fix the FrameIndexes keys in dataloader

Fix the FrameIndexes keys in dataloader;

bob/learn/pytorch/datasets/data_folder.py

@@ -76,6 +76,9 @@ def get_file_names_and_labels(files, data_folder, extension = ".hdf5", hldi_type
 
                     file_keys = list(f_h5py.keys())
 
+                #removes the 'FrameIndexes' key
+                file_keys=[f for f in file_keys if f!='FrameIndexes' ]
+
                 # elements of tuples in the below list are as follows:
                 # a filename a key is extracted from,
                 # a label corresponding to the file,