fix sharness test for ipfs init output

sharness: verbose output

Make sharness tests' output helpful when verbose.
This means cating certain files, or running diagnostic
commands. I used a construction like:

    test_expect_success ".go-ipfs/ has been created" '
      test -d ".go-ipfs" &&
      test -f ".go-ipfs/config" &&
      test -d ".go-ipfs/datastore" ||
      fsh ls -al .go-ipfs
    '

The `|| ...` is a diagnostic run when the preceding command
fails. `fsh` is a trivial script that echoes the args, runs
the cmd, and then also fails, making sure the test case fails.
(wouldnt want the diagnostic accidentally returning true and
making it _seem_ like the test case succeeded).

mount fixes

This commit cleans up how mounting was being done.
It now successfully signals when it is properly mounted
and listen to close signals correctly.

Stream relaying

not sure how it wasnt an error

This commit makes all network tests use ZeroLocalTCPAddress
as the initial peer address, and then relies on
net.ListenAddresses()

This should get rid of the tcp addr clash problems.

The separation of work in the p2p pkg is as follows:

- net implements the Swarm and connectivity
- protocol has muxer and header protocols
- host implements protocol muxing + services
- identify took over handshake completely! yay.
- p2p package works as a whole

using a placeholder net2 package so tests continue to pass.
Will be swapped atomically into main code.

remove comment about spdystream. this is now
superceded by go-peerstream interface.

The net package is the next to move. It will be massaged
a bit still to fix the Network / "NetworkBackend" conflict.

The crypto package moves into p2p. Nothing in it so far is ipfs
specific; everything is p2p-general.

I think it's time to move a lot of the peer-to-peer networking
but-not-ipfs-specific things into its own package: p2p.
This could in the future be split off into its own library.
The first thing to go is the peer.

These services should all be added separately, in a function
that is Network impl independent. The interfaces need to be
massaged a bit (split inet.Network in two), so will do when
needed. For now this is fine.

swarmnet is a better name for the package, because
it's just a Network implemented with a Swarm.
(ipfsnet will be something slightly different).

this is the leadup into NAT traversal.
note: doesn't work yet. hangs the test.