Merge pull request #2025 from yichengq/270

tools: move etcd-migrate to tools

build

@@ -13,5 +13,5 @@ eval $(go env)
 
 go build -o bin/etcd ${REPO_PATH}
 CGO_ENABLED=0 go build -a -ldflags '-s' -o bin/etcdctl ${REPO_PATH}/etcdctl
-go build -o bin/etcd-migrate ${REPO_PATH}/migrate/cmd/etcd-migrate
+go build -o bin/etcd-migrate ${REPO_PATH}/tools/etcd-migrate
 go build -o bin/etcd-dump-logs ${REPO_PATH}/tools/etcd-dump-logs