Fix minor comment in a script

The variable API_HOST is defined below the comment

Signed-off-by: Hui Kang <kangh@us.ibm.com>

hack/local-up-cluster.sh

@@ -62,7 +62,7 @@ EVICTION_PRESSURE_TRANSITION_PERIOD=${EVICTION_PRESSURE_TRANSITION_PERIOD:-"1m"}
 # This script uses docker0 (or whatever container bridge docker is currently using)
 # and we don't know the IP of the DNS pod to pass in as --cluster-dns.
 # To set this up by hand, set this flag and change DNS_SERVER_IP.
-# Note also that you need API_HOST (defined above) for correct DNS.
+# Note also that you need API_HOST (defined below) for correct DNS.
 KUBE_PROXY_MODE=${KUBE_PROXY_MODE:-""}
 ENABLE_CLUSTER_DNS=${KUBE_ENABLE_CLUSTER_DNS:-true}
 ENABLE_NODELOCAL_DNS=${KUBE_ENABLE_NODELOCAL_DNS:-false}