Prevent multiple vault-manager pods from acting

This commit adds new check in the main loop of vault manager
for multiple instances of vault manager. Only one vault manager is
needed, so it will be put on sleep or be
terminated until only one is left

Story: 2010930
Task: 49199

Test Plan:
PASS Bashate
PASS Vault sanity test

Change-Id: I0fd881aa4078528ba3f804087db87069dae58f7e
Signed-off-by: Tae Park <tae.park@windriver.com>

vault-helm/vault-helm/helm-charts/vault-init.yaml

@@ -3282,6 +3282,16 @@ data:
         sleep "$STATUS_RATE"
         exit_on_trap 20
         pickK8sVersion # check if the k8s server version is changed
+
+        count=$( kubectl get pods -n "${VAULT_NS}" \
+            -o jsonpath='{range .items[*]}{.metadata.name}{"\n"}{end}' \
+            | grep "^${VAULT_FN}-manager" | wc -w )
+        if [ "$count" -gt 1 ]; then
+            log $ERROR "Multiple instances of vault manager detected. Waiting until one left"
+            exit_on_trap 21
+            continue
+        fi
+
         rm $WORKDIR/pods.txt
         echo "" > "$PODREC_TMP_F"
         exit_on_trap 11