In android-L, logging is done through the logd daemon.
If logd daemon is available, send logging to logd.
Otherwise, fallback to the legacy mechanism (/dev/log files).

This change adds access/socket/connect calls to interact with the logd.

Fixes golang/go#9398.

Change-Id: I3c52b81b451f5862107d7c675f799fc85548486d
Reviewed-on: https://go-review.googlesource.com/3350Reviewed-by: David Crawshaw <crawshaw@golang.org>