dcap: always set Subject when talking to PnfsManager

EGI-SVG-2020-16939

Motivation:
The door should always set user subject when talks to PnfsManager
(unless all permission checks done locally)

Modification:
Update PnfsSessionHandler#doLogin to set always set the subject
used by PnfsHandler

Result:
PnfsManager can perform full permission check

target: master, 7.0, 6.2, 6.1, 6.0, 5.2
Requires-notes: yes
Requires-book: no

modules/dcache-dcap/src/main/java/diskCacheV111/doors/DCapDoorInterpreterV3.java

@@ -1037,10 +1037,8 @@ protected void doLogin()
         {
             super.doLogin();
             _pnfs = new PnfsHandler(_cell, _settings.getPnfsManager());
-            if (_isUrl || _settings.isAuthorizationRequired()) {
-                _pnfs.setSubject(_subject);
-                _pnfs.setRestriction(_authz);
-            }
+            _pnfs.setSubject(_subject);
+            _pnfs.setRestriction(_authz);
         }
 
         @Override