Use memcache versioning for autotune remote cache (#121748)
Summary: Internal training platform doesn't get updated very frequently, so lets use versioning for memcache.
Test Plan: existing tests
Differential Revision: D54818197
Pull Request resolved: https://github.com/pytorch/pytorch/pull/121748
Approved by: https://github.com/aakhundov, https://github.com/jansel
