Add github.com/go-fsnotify/fsnotify

This new package will be used by the resolvconf updater code in process to resolve #9202.  It is planned to become part of the core Go package set in Go 1.5.  It also has multi-platform support so is a good choice for future Docker clients on os != linux

Docker-DCO-1.1-Signed-off-by: Tianon Gravi <admwiggin@gmail.com>
Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com>