Ticket #362: Fixed bug in user directory.

extensions/guacamole-auth-mysql/src/main/java/net/sourceforge/guacamole/net/auth/mysql/UserDirectory.java

@@ -151,13 +151,16 @@ public class UserDirectory implements Directory<String, User> {
         // Get user
         MySQLUser user = userService.retrieveUser(identifier);
         
+        if(user == null)
+            return null;
+
         // Verify access is granted
         permissionCheckService.verifyUserAccess(this.user_id,
                 user.getUserID(),
                 MySQLConstants.USER_READ);
 
         // Return user
-        return userService.retrieveUser(identifier);
+        return user;
 
     }