[CLAMP] set Mariadb PVC to RWO

Forgot Mariadb PVC in previous commit
(https://gerrit.onap.org/r/c/oom/+/94610).

Change-Id: I9e3d96eab8b6d6ada7d2ab406a8e72249c909aa4
Issue-ID: CLAMP-488
Signed-off-by: Sylvain Desbureaux <sylvain.desbureaux@orange.com>
diff --git a/kubernetes/clamp/charts/mariadb/values.yaml b/kubernetes/clamp/charts/mariadb/values.yaml
index 5f31c79..8bf6100 100644
--- a/kubernetes/clamp/charts/mariadb/values.yaml
+++ b/kubernetes/clamp/charts/mariadb/values.yaml
@@ -70,7 +70,7 @@
   ##   GKE, AWS & OpenStack)
   ##
   # storageClass: "-"
-  accessMode: ReadWriteMany
+  accessMode: ReadWriteOnce
   size: 2Gi
   mountPath: /dockerdata-nfs
   mountSubPath: clamp/mariadb/data