Typo fix "etcd manager"->"etcd-manager"
Typo fix "etcd manager"->"etcd-manager"

In this doc,  "etcd-manager" is written as "“etcd-manager", while in line 28 "etcd manager"
gambol99/kops,robinpercy/kops,blakebarnett/kops,mad01/kops,aledbf/kops,tsupertramp/kops,justinsb/kops,blakebarnett/kops,gambol99/kops,robinpercy/kops,justinsb/kops,tsupertramp/kops,gambol99/kops,mad01/kops,kubernetes/kops,blakebarnett/kops,kubernetes/kops,chrislovecnm/kops,mad01/kops,robinpercy/kops,aledbf/kops,tsupertramp/kops,aledbf/kops,robinpercy/kops,aledbf/kops,gambol99/kops,blakebarnett/kops,mad01/kops,chrislovecnm/kops,kubernetes/kops,justinsb/kops,chrislovecnm/kops,chrislovecnm/kops,tsupertramp/kops