"tahoe start" claims to have started when it didn't (due to port number conflict)

[zooko]

The problem that I reported in #1376 was caused by the gateway failing to start due to the port number already being taken. From its twistd.log:

2011-03-11 11:57:37-0500 [-]   File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/twisted/internet/tcp.py", line 858, in startListening
2011-03-11 11:57:37-0500 [-]     raise CannotListenError, (self.interface, self.port, le)
2011-03-11 11:57:37-0500 [-] twisted.internet.error.CannotListenError: Couldn't listen on any:9996: [Errno 48] Address already in use.

Looking back through my screen buffer, I see that it misled me into thinking that it had started:

$ tahoe start .
STARTING '/Users/zooko/tmp/d/tmp_create'
$