We met a 403 issue with openstack-helm on StarlingX, when we want to update/create/delete metadata from Horizon with admin.
Reproduce steps:
-	Login with admin.
-	Go to flavor/image panel (or other metadata supported panels)
-	Update Metadata of a flavor/image.  The operation will fail and admin will be logged out.
I guess we have some wrong configurations in the horizon helm chart.
Do you know how to enable the metadata modifications in Horizon?

Horizon pod log as below:
172.16.192.64 - - [24/Jun/2019:05:47:16 +0000] "PATCH /api/nova/flavors/2aeab165-e5bb-4cb4-a883-8748bebc3841/extra-specs/ HTTP/1.1" 403 268
172.16.192.64 - - [24/Jun/2019:05:47:16 +0000] "PATCH /api/nova/flavors/2aeab165-e5bb-4cb4-a883-8748bebc3841/extra-specs/ HTTP/1.1" 403 268 "http://10.10.10.2:31000/admin/flavors/" "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:67.0) Gecko/20100101 Firefox/67.0"