Use mongodb charm in k8s installer

- Update JUJU_AGENT_VERSION to 2.8.6
- Use mongodb charm and update needed osm pod specs to point at it

Change-Id: I7c03ae7de6611fcacef35716646ff08bfc1ff988
Signed-off-by: David Garcia <david.garcia@canonical.com>
diff --git a/installers/docker/osm_pods/nbi.yaml b/installers/docker/osm_pods/nbi.yaml
index ea6014e..7fc6595 100644
--- a/installers/docker/osm_pods/nbi.yaml
+++ b/installers/docker/osm_pods/nbi.yaml
@@ -47,7 +47,7 @@
       initContainers:
       - name: kafka-mongo-test
         image: alpine:latest
-        command: ["sh", "-c", "until (nc -zvw1 kafka 9092 && nc -zvw1 mongo 27017); do sleep 3; done; exit 0"]
+        command: ["sh", "-c", "until (nc -zvw1 kafka 9092 && nc -zvw1 mongodb-k8s 27017); do sleep 3; done; exit 0"]
       containers:
       - name: nbi
         image: opensourcemano/nbi:8
@@ -55,8 +55,8 @@
         - containerPort: 9999
           protocol: TCP
         env:
-         - name: OSMNBI_DATABASE_HOST
-           value: mongo
+         - name: OSMNBI_DATABASE_URI
+           value: mongodb://mongodb-k8s:27017/?replicaSet=rs0
          - name:  OSMNBI_MESSAGE_HOST
            value: kafka
         envFrom: