Update /etc/hosts when linked container is restarted

Carry of #7092

closes #7092
fixes #6350

/cc @vieux
I don’t think that’s necessary; the next time the container starts the file will be rewritten anyhow.

-Erik

> On Aug 22, 2014, at 1:48 AM, Alexandr Morozov <notifications@github.com> wrote:
> 
> In daemon/container.go:
> 
> > @@ -297,6 +297,9 @@ func (container *Container) Start() (err error) {
> >  	if err := container.initializeNetworking(); err != nil {
> >  		return err
> >  	}
> > +	if err := container.updateParentsHosts(); err != nil {
> I wonder if we need to remove records from hosts on container stop.
> 
> —
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