let me know if this looks off @whyrusleeping @jbenet

it's unclear what this test case is meant to protect, but passing an empty datastore value no longer has bearing on node construction. Datastore setup now occurs in repo.

p2p/net/swarm: fixed bugs in swarm err closes

p2p/net/swarm: dial once at a time

p2p/net/swarm: fix connect self problems

This adds two checks after a successful conn.Dial
* if the remote peer is not who we wanted, close conn
* if the remove peer is outselves, close conn

(the second is redundant, but the codebase may evolve to
end up disabling the first check, so keeping the second
in place helps)

note:
Loopback addresses are actually sent out (they _have to be_,
in cases where there are >1 node in the same machine), so
many times when trying connections, nodes end up dialing
themselves.

dont send ip6 link local addrs