Merge multiple functions for creating consul containers into one. (#6612)

Merge both functions for creating mongodb containers into one.
Add retries to docker container cleanups.
Require $VAULT_ACC be set to enable AWS tests.

builtin/logical/postgresql/backend_test.go

@@ -11,6 +11,7 @@ import (
 	"reflect"
 	"testing"
 
+	"github.com/hashicorp/vault/helper/testhelpers/docker"
 	logicaltest "github.com/hashicorp/vault/helper/testhelpers/logical"
 	"github.com/hashicorp/vault/sdk/logical"
 	"github.com/lib/pq"
@@ -34,10 +35,7 @@ func prepareTestContainer(t *testing.T) (cleanup func(), retURL string) {
 	}
 
 	cleanup = func() {
-		err := pool.Purge(resource)
-		if err != nil {
-			t.Fatalf("Failed to cleanup local container: %s", err)
-		}
+		docker.CleanupResource(t, pool, resource)
 	}
 
 	retURL = fmt.Sprintf("postgres://postgres:secret@localhost:%s/database?sslmode=disable", resource.GetPort("5432/tcp"))