volumes: remove usage of secret placeholder

dashboard/src/constants.js

@@ -119,8 +119,6 @@ const ENDPOINTS_OVH = [
     { name: 'Kimsufi North-America', value: 'kimsufi-ca' },
 ];
 
-const SECRET_PLACEHOLDER = String.fromCharCode(0x25CF).repeat(8);
-
 // List is from http://docs.aws.amazon.com/general/latest/gr/rande.html#s3_region
 const REGIONS_S3 = [
     { name: 'Africa (Cape Town)', value: 'af-south-1' },
@@ -334,7 +332,6 @@ export {
     PROXY_APP_ID,
     TOKEN_TYPES,
     ENDPOINTS_OVH,
-    SECRET_PLACEHOLDER,
     STORAGE_PROVIDERS,
     BACKUP_FORMATS,
     REGIONS_CONTABO,
@@ -366,7 +363,6 @@ export default {
     PROXY_APP_ID,
     TOKEN_TYPES,
     ENDPOINTS_OVH,
-    SECRET_PLACEHOLDER,
     STORAGE_PROVIDERS,
     BACKUP_FORMATS,
     REGIONS_CONTABO,