e2e: fix OLM version skew testing

#1052 simplified the make rules
for the OLM bundle. However, that had the effect that those rules now
no longer can build the OLM bundle for the previous release, 1.0.1, which
caused version skew testing to fail.

The solution is to run make in the 1.0.1 source directory and thus use
the make rules from that release. This is cleaner, too.

test/e2e/deploy/deploy.go

@@ -1246,7 +1246,7 @@ func EnsureDeploymentNow(f *framework.Framework, deployment *Deployment) {
 		// generated oln-bundles under /deploy in the source tree.
 		if deployment.HasOLM {
 			make := exec.Command("make", "operator-generate-bundle", "VERSION="+tag, "REPO_ROOT="+workRoot)
-			make.Dir = root
+			make.Dir = workRoot
 			make.Env = env
 			_, err := pmemexec.Run(ctx, make)
 			framework.ExpectNoError(err, "%s: generate bundle for operator version %s", deployment.Name(), deployment.Version)