nfs4: remove state only after successful disposal

Motivation:
When client disposes client state, for example open state on close, then
some child states might fail to release resources and force a client to
retry the request. However, if state is not associated with the
NFSClient, then retry will fail with BAD_STATETID.

Modification:
Remove state only after successful disposal.

Result:
Fix BAD_STATETID error on in case of nested states (delegation, lock,
layout)

Acked-by: Paul Millar
Target: master, 0.24, 0.23

core/src/main/java/org/dcache/nfs/v4/NFS4Client.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009 - 2022 Deutsches Elektronen-Synchroton,
+ * Copyright (c) 2009 - 2023 Deutsches Elektronen-Synchroton,
  * Member of the Helmholtz Association, (DESY), HAMBURG, GERMANY
  *
  * This library is free software; you can redistribute it and/or modify
@@ -328,11 +328,12 @@ public NFS4State createState(StateOwner stateOwner, NFS4State openState) throws
         if (openState != null) {
             openState.addDisposeListener(s -> {
                 // remove and dispose derived states.
-                NFS4State nfsState = _clientStates.remove(state.stateid());
+                NFS4State nfsState = _clientStates.get(state.stateid());
                 if (nfsState != null) {
                     _log.debug("removing derived state {}", nfsState);
                     nfsState.tryDispose();
                 }
+                _clientStates.remove(state.stateid());
             });
         }
         _clientStates.put(state.stateid(), state);