This change makes the etcd package compatible with the existing Go
ecosystem for module versioning.
Used this tool to update package imports:
https://github.com/KSubedi/gomove
A call file.Sync on OSX doesn't guarantee actual persistence on
physical drive media as the data can be cached in physical drive's
buffers. Hence calls to file.Sync need to be replaced with
fcntl(F_FULLFSYNC).
etcd might generate incomplete proxy config file after a power failure.
It is because we use ioutil.WriteFile. And iotuile.WriteFile does
not call Sync before closing the file.
Brandon Philips