Fix KOLLA_CONFIG_STRATEGY in neutron agents

The change from:
I01220077d8d25db5f69802ad27e745d90826d69b

In some way was lost by the gerrit.  This patch just basically
redoes that work so the neutron agents will work properly.

Change-Id: I92ac1b8601d145a0722b37eda937ee2baac7a7c5
Closes-Bug: #1489664

docker/neutron/neutron-agents/neutron-dhcp-agent/start.sh

@@ -12,10 +12,10 @@ source /opt/kolla/config-sudoers.sh
 # this one.
 set_configs() {
     case $KOLLA_CONFIG_STRATEGY in
-        CONFIG_EXTERNAL_COPY_ALWAYS)
+        COPY_ALWAYS)
             source /opt/kolla/neutron-dhcp-agent/config-external.sh
             ;;
-        CONFIG_EXTERNAL_COPY_ONCE)
+        COPY_ONCE)
             if [[ -f /configured-dhcp ]]; then
                 echo 'INFO - Neutron-dhcp has already been configured; Refusing to copy new configs'
                 return

docker/neutron/neutron-agents/neutron-l3-agent/start.sh

@@ -12,10 +12,10 @@ source /opt/kolla/config-sudoers.sh
 # this one.
 set_configs() {
     case $KOLLA_CONFIG_STRATEGY in
-        CONFIG_EXTERNAL_COPY_ALWAYS)
+        COPY_ALWAYS)
             source /opt/kolla/neutron-l3-agent/config-external.sh
             ;;
-        CONFIG_EXTERNAL_COPY_ONCE)
+        COPY_ONCE)
             if [[ -f /configured-l3 ]]; then
                 echo 'INFO - Neutron-l3 has already been configured; Refusing to copy new configs'
                 return

docker/neutron/neutron-agents/neutron-metadata-agent/start.sh

@@ -12,10 +12,10 @@ source /opt/kolla/config-sudoers.sh
 # this one.
 set_configs() {
     case $KOLLA_CONFIG_STRATEGY in
-        CONFIG_EXTERNAL_COPY_ALWAYS)
+        COPY_ALWAYS)
             source /opt/kolla/neutron-metadata-agent/config-external.sh
             ;;
-        CONFIG_EXTERNAL_COPY_ONCE)
+        COPY_ONCE)
             if [[ -f /configured-md ]]; then
                 echo 'INFO - Neutron-metadata has already been configured; Refusing to copy new configs'
                 return