Need to improve the exception msg on discovery failures

When a discovery failure occurs we are only reporting the original exception that triggered discovery. This codeblock does not try to incorporate the discovery exception seen if there already is a serverEx:

try

{ naming = discoverServer(refEnv); }

catch (Exception e)

{ discoveryFailure = e; if (serverEx == null) serverEx = e; }

We should be building a better nested exception to show both problem.s