Replace unavailable ntp servers

Now internal ntp servers are not maintained anymore, so use ubuntu ntp servers
by default.

Related-Prod: https://mirantis.jira.com/browse/PRODX-49305
Change-Id: Idec2081d4f3891a76d5072384a83eff44fe102aa
diff --git a/de/heat-templates/scripts/functions.sh b/de/heat-templates/scripts/functions.sh
index 18e4eaf..cfc9420 100644
--- a/de/heat-templates/scripts/functions.sh
+++ b/de/heat-templates/scripts/functions.sh
@@ -61,7 +61,7 @@
 # Change default VXLAN port, need for https://mirantis.jira.com/browse/PRODX-11679
 UCP_DOCKER_SWARM_DATA_PORT=${UCP_DOCKER_SWARM_DATA_PORT:-4789}
 UCP_DOCKER_CALICO_VXLAN_PORT=${UCP_DOCKER_CALICO_VXLAN_PORT:-${UCP_DOCKER_SWARM_DATA_PORT}}
-NTP_SERVERS=${NTP_SERVERS:-"ldap.scc.mirantis.net ldap.bud.mirantis.net"}
+NTP_SERVERS=${NTP_SERVERS:-"0.ubuntu.pool.ntp.org 1.ubuntu.pool.ntp.org 2.ubuntu.pool.ntp.org 3.ubuntu.pool.ntp.org"}
 IRONIC_BAREMETAL_VXLAN_INTERFACE='vxlan10'
 HUGE_PAGES_1G_SIZE=$(echo "${HUGE_PAGES}" | awk -F ',' '{print $1}')
 HUGE_PAGES_2Mb_SIZE=$(echo "${HUGE_PAGES}" | awk -F ',' '{print $2}')