crash when using /option in linux

[Charlie Poole]

Reported via email by Daniel Nauck:

If you call "$ mono nunit-console.exe myTestAsm.dll /nologo" then nunit
crashes:

========================================================================
NUnit version 2.5.1.9189
Copyright (C) 2002-2009 Charlie Poole.
Copyright (C) 2002-2004 James W. Newkirk, Michael C. Two, Alexei A.
Vorontsov.
Copyright (C) 2000-2002 Philip Craig.
All Rights Reserved.

Runtime Environment -
   OS Version: Unix 2.6.18.6
  CLR Version: 2.0.50727.1433 ( Mono 2.5 )

ProcessModel: Default DomainUsage: Multiple
Execution Runtime: mono-2.0.50727.1433
Unhandled Exception:
System.NullReferenceException: Object reference not set to an instance of an object

Server stack trace:
  at NUnit.Core.SimpleTestRunner.CountTestCases (ITestFilter filter) [0x00000]
  at NUnit.Core.ProxyTestRunner.CountTestCases (ITestFilter filter) [0x00000]
  at NUnit.Core.ProxyTestRunner.CountTestCases (ITestFilter filter) [0x00000]
  at (wrapper xdomain-dispatch)
NUnit.Core.ProxyTestRunner:CountTestCases (object,byte[]&,byte[]&)

Exception rethrown at [0]:

  at (wrapper xdomain-invoke) NUnit.Core.ProxyTestRunner:CountTestCases
(NUnit.Core.ITestFilter)
  at NUnit.Core.ProxyTestRunner.CountTestCases (ITestFilter filter) [0x00000]
  at NUnit.Util.AggregatingTestRunner.CountTestCases (ITestFilter
filter) [0x00000]
  at NUnit.Util.AggregatingTestRunner.Run (EventListener listener, ITestFilter filter) [0x00000]
  at NUnit.ConsoleRunner.ConsoleUi.Execute
(NUnit.ConsoleRunner.ConsoleOptions options) [0x00000]
  at NUnit.ConsoleRunner.Runner.Main (System.String[] args) [0x00000] ========================================================================

While this works on Windows/.NET.

If you use the "-" as flag, it works.

This should give a message that /nologo cannot be found rather than crashing.