daemon/demo: avoid duplicate option on restart

If the demo container is restarted then the warning option in the ceph
configuration file about the pool without redundancy will be set again
even if it is already present.

Signed-off-by: Dimitri Savineau <dsavinea@redhat.com>
(cherry picked from commit 2bb051a)

src/daemon/start_mon.sh

@@ -183,7 +183,9 @@ function start_mon {
   # start MON
   if [[ "$CEPH_DAEMON" == demo ]]; then
     if [[ ! "${CEPH_VERSION}" =~ ^(luminous|mimic)$ ]]; then
-      echo "mon warn on pool no redundancy = false" >> /etc/ceph/"${CLUSTER}".conf
+      if ! grep -qE "mon warn on pool no redundancy = false" /etc/ceph/"${CLUSTER}".conf; then
+          echo "mon warn on pool no redundancy = false" >> /etc/ceph/"${CLUSTER}".conf
+      fi
     fi
     /usr/bin/ceph-mon "${DAEMON_OPTS[@]}" -i "${MON_NAME}" --mon-data "$MON_DATA_DIR" --public-addr "${MON_IP}"