Fix NPE while expanding %{p} (JSPF-99)
diff --git a/resolver/src/main/java/org/apache/james/jspf/core/MacroExpand.java b/resolver/src/main/java/org/apache/james/jspf/core/MacroExpand.java
index 8d03b94..6ac2d1e 100644
--- a/resolver/src/main/java/org/apache/james/jspf/core/MacroExpand.java
+++ b/resolver/src/main/java/org/apache/james/jspf/core/MacroExpand.java
@@ -150,6 +150,8 @@
                 // just return the default "unknown".
                 session.setClientDomain("unknown");
             }
+                    
+            session.setClientDomain("unknown");        
             return null;
 
         }
@@ -585,4 +587,4 @@
         return sb.toString();
     }
 
-}
\ No newline at end of file
+}