Revert "be sure to close connection after completion of xfr out. (#2866)" (#2872)
Revert "be sure to close connection after completion of xfr out. (#2866)" (#2872)

This reverts commit a657e1f6618ee94c46fa9374dd29c21345710d38.
miekg/coredns,johnbelamaric/coredns,ii/coredns,ii/coredns,miekg/coredns,chrisohaver/coredns,johnbelamaric/coredns,yongtang/coredns,coredns/coredns