baremetal: Template RHCOS_IMAGE_URL in startironic.sh

This shouldn't be hard-coded, so instead we replace the URL with the
appropriate data from rhcos.json.

Related: openshift-metal3#37

data/data/bootstrap/baremetal/files/usr/local/bin/startironic.sh → data/data/bootstrap/baremetal/files/usr/local/bin/startironic.sh.template

@@ -7,8 +7,8 @@ IRONIC_INSPECTOR_IMAGE=${IRONIC_INSPECTOR_IMAGE:-"quay.io/metal3-io/ironic-inspe
 IPA_DOWNLOADER_IMAGE=${IPA_DOWNLOADER_IMAGE:-"quay.io/metal3-io/ironic-ipa-downloader:master"}
 COREOS_DOWNLOADER_IMAGE=${COREOS_DOWNLOADER_IMAGE:-"quay.io/openshift-metal3/rhcos-downloader:master"}
 
-# FIXME this should be provided by the installer
-RHCOS_IMAGE_URL="https://releases-art-rhcos.svc.ci.openshift.org/art/storage/releases/ootpa/410.8.20190520.0"
+# This image is templated in via the installer pkg/asset/ignition/bootstrap/bootstrap.go
+RHCOS_IMAGE_BASE_URL="{{.RHCOSBaseURI}}"
 
 # First we stop any previously started containers, because ExecStop only runs when the ExecStart process
 # e.g this script is still running, but we exit if *any* of the containers exits unexpectedly
@@ -76,7 +76,7 @@ podman run -d --net host --name ipa-downloader \
 
 podman run -d --net host --name coreos-downloader \
      --env CACHEURL="http://172.22.0.1/images" \
-     -v $IRONIC_SHARED_VOLUME:/shared:z ${COREOS_DOWNLOADER_IMAGE} /usr/local/bin/get-resource.sh $RHCOS_IMAGE_URL
+     -v $IRONIC_SHARED_VOLUME:/shared:z ${COREOS_DOWNLOADER_IMAGE} /usr/local/bin/get-resource.sh $RHCOS_IMAGE_BASE_URL
 
 # Start the conductor so db sync can happen while images download
 sudo podman run -d --net host --privileged --name ironic-conductor \