vfs: add xattr access modes to the mask

Motivation:
the ACCESS4_XAREAD  ACCESS4_XAWRITE  ACCESS4_XALIST access
modes should be recognized by the server as valid values.

Modification:
add xattr access modes to the mask

Result:
server accepts xattr access masks.

Acked-by: Lea Morschel
Target: master, 0.20

core/src/main/java/org/dcache/nfs/vfs/PseudoFs.java

@@ -69,7 +69,8 @@ public class PseudoFs extends ForwardingFileSystem {
 
     private final static int ACCESS4_MASK =
             ACCESS4_DELETE | ACCESS4_EXECUTE | ACCESS4_EXTEND
-            | ACCESS4_LOOKUP | ACCESS4_MODIFY | ACCESS4_READ;
+            | ACCESS4_LOOKUP | ACCESS4_MODIFY | ACCESS4_READ
+            | ACCESS4_XAREAD | ACCESS4_XAWRITE | ACCESS4_XALIST;
 
     public PseudoFs(VirtualFileSystem inner, RpcCall call, ExportTable exportTable) {
         _inner = inner;