nfs: update show pools command to display pure IPs

Motivation:
The output tries to print unresolved host names which makes it a bit
unreadable:

poolA: DS: 00000001000000000000000000000000, InetAddress: [/[2001:638::22]:33141, /131.1.6.4:33141]

Modification:
Manually convert an array of InetSocketAddress to a string form.

Result:

poolA: DS: 00000001000000000000000000000000, InetAddress: [[2001:638::22]:33141, 131.1.6.4:33141]

Acked-by: Paul Millar
Target: master
Require-book: no
Require-notes: no

Author: kofemann

modules/dcache-nfs/src/main/java/org/dcache/chimera/nfsv41/door/NFSv41Door.java

@@ -1395,10 +1395,19 @@ public String getName() {
             return _name;
         }
 
+        /**
+         * Convert array of InetSocketAddress to a string representation.
+         */
+        private static String addrArrayToString(InetSocketAddress[] addresses) {
+            return Stream.of(addresses)
+                    .map(s -> InetAddresses.toUriString(s.getAddress()) + ":" + s.getPort())
+                    .collect(Collectors.joining(", ", "[", "]"));
+        }
+
         @Override
         public String toString() {
             return String.format("%s: DS: %s, InetAddress: %s",
-                  _name, _deviceId, Arrays.toString(_socketAddress));
+                  _name, _deviceId, addrArrayToString(_socketAddress));
         }
     }