Add volumes and env vars to helm hook test pod

 - Uses the same extraEnvironmentVars, volumes and volumeMounts set on
   the server statefulset to configure the Vault server test pod used by
   the helm test hook
 - This is necessary in situations where TLS is configured, but the
   certificates are not affiliated with the k8s CA / part of k8s PKI

 - Fixes hashicorpGH-665

templates/tests/server-test.yaml

@@ -15,6 +15,7 @@ spec:
       env:
         - name: VAULT_ADDR
           value: {{ include "vault.scheme" . }}://{{ template "vault.fullname" . }}.{{ .Release.Namespace }}.svc:{{ .Values.server.service.port }}
+        {{- include "vault.extraEnvironmentVars" .Values.server | nindent 8 }}
       command:
         - /bin/sh
         - -c
@@ -35,6 +36,13 @@ spec:
           fi
 
           exit 0
-
+      volumeMounts:
+        {{- if .Values.server.volumeMounts }}
+          {{- toYaml .Values.server.volumeMounts | nindent 12}}
+        {{- end }}
+  volumes:
+    {{- if .Values.server.volumes }}
+      {{- toYaml .Values.server.volumes | nindent 8}}
+    {{- end }}
   restartPolicy: Never
 {{- end }}