lease maintenance code cannot call `stat_shares`
It fails with a Foolscap violation:
2020-02-25T15:40:33-0500 [-] Fuzzy timer service (lease maintenance service)
Traceback (most recent call last):
File "/nix/store/4ba7dicrqyiazsmwgqjj8p9xwx800gap-python-2.7.17-env/lib/python2.7/site-packages/twisted/internet/defer.py", line 151, in maybeDeferred
result = f(*args, **kw)
File "/nix/store/4ba7dicrqyiazsmwgqjj8p9xwx800gap-python-2.7.17-env/lib/python2.7/site-packages/_zkapauthorizer/lease_maintenance.py", line 402, in <lambda>
maintain_leases,
File "/nix/store/4ba7dicrqyiazsmwgqjj8p9xwx800gap-python-2.7.17-env/lib/python2.7/site-packages/twisted/internet/defer.py", line 1613, in unwindGenerator
return _cancellableInlineCallbacks(gen)
File "/nix/store/4ba7dicrqyiazsmwgqjj8p9xwx800gap-python-2.7.17-env/lib/python2.7/site-packages/twisted/internet/defer.py", line 1529, in _cancellableInlineCallbacks
_inlineCallbacks(None, g, status)
--- <exception caught here> ---
File "/nix/store/4ba7dicrqyiazsmwgqjj8p9xwx800gap-python-2.7.17-env/lib/python2.7/site-packages/twisted/internet/defer.py", line 1418, in _inlineCallbacks
result = g.send(result)
File "/nix/store/4ba7dicrqyiazsmwgqjj8p9xwx800gap-python-2.7.17-env/lib/python2.7/site-packages/_zkapauthorizer/controller.py", line 750, in bracket
result = yield between()
foolscap.tokens.Violation: Violation: ('RIStorageServer.tahoe.allmydata.com(<RemoteReference at 0x7fc143290c10 [pb://ysj4...@tcp:x.x.x.x:8898/3nml...]>) does not offer stat_shares',)