refresh cassandra repo

  * Mark few files like depracated
  * Add corresponding debmirror

Related-Bug: PROD-17862 (PROD:17862)

Change-Id: Ie44ed9400ab714582e62a2e733f3f574c315736e
diff --git a/linux/system/repo_local/docker_legacy.yml b/linux/system/repo_local/docker_legacy.yml
index d12cc0d..3df198f 100644
--- a/linux/system/repo_local/docker_legacy.yml
+++ b/linux/system/repo_local/docker_legacy.yml
@@ -1,3 +1,5 @@
+# DEPRECATED since 2018.7+ release.
+# Please use system/repo/mcp/apt_mirantis
 parameters:
   linux:
     system:
@@ -6,4 +8,4 @@
           refresh_db: ${_param:linux_repo_refresh_db}
           source: "deb [arch=amd64] http://${_param:local_repo_url}/ubuntu-${_param:linux_system_codename}/ ${_param:apt_mk_version} docker-legacy"
           architectures: amd64
-          key_url: "http://${_param:local_repo_url}/public.gpg"
\ No newline at end of file
+          key_url: "http://${_param:local_repo_url}/public.gpg"