horizon: Correct location of monitoring_policy file

Patch to correctly copy monitoring_policy.json into
/etc/openstack-dashboard.  Policy was misplaced, and not being enforced.

Note that by current default policy, admin doesn't not have Monitoring
access.

Closes-Bug: #1928408
Change-Id: I4faabdfa9c273fc61b536e6ce88b8d71ab2fc581
(cherry picked from commit f68dfb8)

Author: Scott Shambarger

docker/horizon/extend_start.sh

@@ -160,7 +160,7 @@ function config_monasca_ui {
         "${SITE_PACKAGES}/openstack_dashboard/local/enabled/_50_admin_add_monitoring_panel.py"
     config_dashboard "${ENABLE_MONASCA:-no}" \
         "${SITE_PACKAGES}/monitoring/conf/monitoring_policy.json" \
-        "${SITE_PACKAGES}/openstack_dashboard/conf/monitoring_policy.json"
+        "/etc/openstack-dashboard/monitoring_policy.json"
 }
 
 function config_murano_dashboard {

releasenotes/notes/bug-1928408-4a22a85570eee8d6.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    Fixes location of monitoring_policy in Horizon, so access
+    policy is correctly enforced.  Note that by current default,
+    admin doesn't not have Monitoring access.
+    `LP#1928408 <https://launchpad.net/bugs/1928408>`__