Adding VIM refresh period to RO charm config

Refresh period is allowed >=60 or -1. Setting it -1
will disable the updating VM status.

Change-Id: I94ec37f68303128ba7af67f14121436005fd9259
Signed-off-by: aticig <gulsum.atici@canonical.com>
diff --git a/installers/charm/ro/config.yaml b/installers/charm/ro/config.yaml
index 8c5740a..31bf8cb 100644
--- a/installers/charm/ro/config.yaml
+++ b/installers/charm/ro/config.yaml
@@ -35,6 +35,15 @@
     description: "Log Level"
     type: string
     default: "INFO"
+  period_refresh_active:
+    type: int
+    description: |
+      Updates the VNF status from VIM for every given period of time seconds.
+      Values equal or greater than 60 is allowed.
+      Disable the updates from VIM by setting -1.
+      Example:
+        $ juju config ro period_refresh_active=-1
+        $ juju config ro period_refresh_active=100
   mysql_host:
     type: string
     description: MySQL Host (external database)