Fix dbPath typo in templates/mongodb.json.j2

During mongodb upgrade process "/var/lib/mongodb" should have
correct permissions, but a typo present in config.json was giving
permissions to "/var/lib/kolla/mongodb"

Change-Id: I916e7d831531131b2f141a2f7ac712d4a82f7e86
Closes-Bug: #1668303

ansible/roles/mongodb/templates/mongodb.json.j2

@@ -10,7 +10,7 @@
     ],
     "permissions": [
         {
-            "path": "/var/lib/kolla/mongodb",
+            "path": "/var/lib/mongodb",
             "owner": "mongodb:mongodb",
             "recurse": true
         },