Clarify the root directory comment
Clarify the root directory comment

A contributor had an issue when ran script changing the directory
name after clone. This was discussed on the etcd slack channel.

gyuho/etcd,etcd-io/etcd,mkumatag/etcd,mqliang/etcd,gyuho/etcd,etcd-io/etcd,rnaveiras/etcd,ajityagaty/etcd,coreos/etcd,mkumatag/etcd,rnaveiras/etcd,ajityagaty/etcd,coreos/etcd,ajityagaty/etcd,mqliang/etcd,mqliang/etcd,etcd-io/etcd,mkumatag/etcd,rnaveiras/etcd