In this commit (2014 for v1.02) Purge was implemented for the local
backend:
1527e64ee756e32b local: Implement Purger interface
This appeared to be implemented just to make a Purge and doesn't
appear to do anything useful.
It is in fact significatly worse than the rclone fallback purge since
it doesn't operate in parallel or update stats.
This patch removes the Purge routine for a consequent speed up and
showing of stats.
See: https://forum.rclone.org/t/progress-flag-for-rclone-purge/44416