roachtest: fix for tpcc tests against older versions

Add the `--deprecated-fk-indexes` flag when using a fixture (and not
just `init`).

Note that although this is the right thing to do, we don't have these
fixtures yet. Unfortunately, 20.1 and older aren't able to load
backups created by 20.2 in the first place.

Release note: None

pkg/cmd/roachtest/tpcc.go

@@ -137,6 +137,10 @@ func setupTPCC(
 	c.Put(ctx, cockroach, "./cockroach", workloadNode)
 	c.Put(ctx, workload, "./workload", workloadNode)
 
+	extraArgs := opts.ExtraSetupArgs
+	if !t.buildVersion.AtLeast(version.MustParse("v20.2.0")) {
+		extraArgs += " --deprecated-fk-indexes"
+	}
 	func() {
 		db := c.Conn(ctx, 1)
 		defer db.Close()
@@ -145,14 +149,13 @@ func setupTPCC(
 		switch opts.SetupType {
 		case usingFixture:
 			t.Status("loading fixture")
-			c.Run(ctx, workloadNode, tpccFixturesCmd(t, cloud, opts.Warehouses, opts.ExtraSetupArgs))
+			c.Run(ctx, workloadNode, tpccFixturesCmd(t, cloud, opts.Warehouses, extraArgs))
 		case usingInit:
 			t.Status("initializing tables")
-			cmd := fmt.Sprintf("./workload init tpcc --warehouses=%d %s {pgurl:1}",
-				opts.Warehouses, opts.ExtraSetupArgs)
-			if !t.buildVersion.AtLeast(version.MustParse("v20.2.0")) {
-				cmd += " --deprecated-fk-indexes"
-			}
+			cmd := fmt.Sprintf(
+				"./workload init tpcc --warehouses=%d %s {pgurl:1}",
+				opts.Warehouses, extraArgs,
+			)
 			c.Run(ctx, workloadNode, cmd)
 		default:
 			t.Fatal("unknown tpcc setup type")