Small fixes in: FSL ground truth and UpdateExampleReadmes.py script

This pull request include:
- Some fixes in the FSL ground truth example 001 that are needed in order for the tests to be computed at incf-nidash/nidm-results_fsl.
- In `UpdateExampleReadmes.py` script, each example `provn` file is now compared to the Prov Store document desribed in the corresponding README (instead of the last document with the same title on the ProvStore).