Release: fix Makefile
Release: fix Makefile

Latest refactoring fubar-ed Makefile.release. Fix the Linux build
target.

varyoo/coredns,johnbelamaric/coredns,chrisohaver/coredns,miekg/coredns,miekg/coredns,ii/coredns,yongtang/coredns,jremond/coredns,jremond/coredns,ii/coredns,johnbelamaric/coredns,coredns/coredns