Revert "lib,src: add unix socket getsockname/getpeername"
This reverts commit 6cd0e266. This reverts commit 7a999a13. This reverts commit f3375954.
It turns out that on Windows, uv_pipe_getsockname() is a no-op for client sockets. It slipped through testing because of a CI snafu.
CI: https://jenkins-iojs.nodesource.com/job/node-test-pull-request/193/