Fix default address typo in health README
Fix default address typo in health README

jremond/coredns,ii/coredns,miekg/coredns,varyoo/coredns,johnbelamaric/coredns,Infoblox-CTO/coredns,yongtang/coredns,miekg/coredns,Infoblox-CTO/coredns,Infoblox-CTO/coredns,chrisohaver/coredns,ii/coredns,jremond/coredns,coredns/coredns,johnbelamaric/coredns