config: change syntax of no-listen mode

[warner]

We now use::

tub.port = disabled
tub.location = disabled

instead of using an empty value (but the key still being present, since
if the key is missing entirely, that means "be automatic").

closes ticket:2816

[coveralls]

Coverage decreased (-0.01%) to 92.231% when pulling 6f40ce9 on warner:2816-nolisten-syntax into a03f68b on tahoe-lafs:master.

[david415]

looks good to me! the travis build is failing on darwin/osx because

exceptions.ImportError: No module named txi2p.sam

[warner]

Yeah, something weird is going on, I think the pip install process failed halfway through, so missing txi2p is only a fraction of the real problem. I'll look into it.

[warner]

Huh, the log showed the pycryptopp build failing when cc failed to find a source file named src-cryptopp/serpent.cpp. That file is present in the tarball I just downloaded.. I'm starting to suspect that the host machine ran out of disk space, and failed to notice, and the tarball was not unpacked completely. I've forced a rebuild on travis, let's see if that clears up the problem.

[warner]

Ok, now we're down to the current version-mismatch problem that will be resolved when #327 lands. (txtorcon removing the old arguments means we'll have this in-between period when the current versions of tahoe, foolscap, and txtorcon are not compatible with each other). When that lands, I'll re-push, and this should start working again.

[coveralls]

Coverage increased (+0.005%) to 92.229% when pulling 2738061 on warner:2816-nolisten-syntax into 78ccae3 on tahoe-lafs:master.

[coveralls]

Coverage increased (+0.006%) to 92.235% when pulling 076b389 on warner:2816-nolisten-syntax into a1594df on tahoe-lafs:master.

[meejah]

re: #328 (comment) just following up some IRC discussion to say that the old args (socks_hostname=, socks_port=) should still work; it's a txtorcon bug if not.

[warner]

Meejah's right, it's my bad, I failed to make the new Foolscap release backwards compatible (we removed foolscap.connections.tor.socks_port() when adding socks_endpoint()), so Tahoe before PR #327 couldn't use the latest foolscap. Sorry bout that!