made it possible to distinguish "no such user" from "I don't know if there's such an user", so that the UI can use this to improve error diagnostics.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@14871 71c3de6d-444a-0410-be80-ed276b4c234a

Originally-Committed-As: 23bafefcf3b254c76f7d2744523bf117f37b9d88

core/src/main/java/hudson/security/LDAPSecurityRealm.java

@@ -187,7 +187,7 @@ public class LDAPSecurityRealm extends SecurityRealm {
                         return ldapSerach.searchForUser(username);
                     } catch (LdapDataAccessException e) {
                         LOGGER.log(Level.WARNING, "Failed to search LDAP for username="+username,e);
-                        throw new UsernameNotFoundException(e.getMessage(),e);
+                        throw new UserMayOrMayNotExistException(e.getMessage(),e);
                     }
                 }
             });