ExecTestCase should support args

parrot use it to run a vm with a script, to test pynie..

> === modified file 'python/subunit/__init__.py'
> --- python/subunit/__init__.py 2009-03-18 09:33:42 +0000
> +++ python/subunit/__init__.py 2009-03-29 23:59:06 +0000
> @@ -429,7 +429,7 @@
>
> def _run(self, result):
> protocol = TestProtocolServer(result)
> - output = subprocess.Popen([self.script],
> + output = subprocess.Popen(self.script,
>
> stdout=subprocess.PIPE).communicate()[0]
> protocol.readFrom(StringIO(output))
>
>
> may let it work for you with arguments [not tested].

Ah-ha! It needed one more fix, which is:

> + output = subprocess.Popen(self.script, shell=True,