TT#177550 Check for new /etc/ngcp-config/sites/current symlink

We check that when the pathname exists it is a symlink. We will perform
further consistency checks from «ngcpcfg check».

Change-Id: I3850d9cf23fd77b926d08ae47a6969cac1790cf0

templates/131_filesys-ngcp-pro.yaml.tt2

@@ -5,6 +5,26 @@
 -%]
 file:
 
+  /etc/ngcp-config/sites:
+    exists:
+      or:
+        - true
+        - false
+    mode: "0755"
+    owner: root
+    group: root
+    filetype: directory
+
+  /etc/ngcp-config/sites/current:
+    exists:
+      or:
+        - true
+        - false
+    mode: "0777"
+    owner: root
+    group: root
+    filetype: symlink
+
   /etc/ngcp-config/shared-files:
     exists: true
     mode: "0755"