kola/podman.go: use fedora container in podman.workflow

This test has been denylisted in FCOS due to rate limiting issues with
the nginx container, causing frequent timeouts and failures. Replace the
nginx container with the `fedora:latest` container from quay.io to
mitigate this. Also modify the `podman run` command to start a Python
HTTP server to continue testing volume mounting and port forwarding.

mantle/kola/tests/podman/podman.go

@@ -129,16 +129,17 @@ func podmanWorkflow(c cluster.TestCluster) {
 	m := c.Machines()[0]
 
 	// Test: Verify container can run with volume mount and port forwarding
-	image := "docker.io/library/nginx"
-	wwwRoot := "/usr/share/nginx/html"
+	image := "quay.io/fedora/fedora"
+	wwwRoot := "/var/html"
 	var id string
 
 	c.Run("run", func(c cluster.TestCluster) {
 		dir := c.MustSSH(m, `mktemp -d`)
 		cmd := fmt.Sprintf("echo TEST PAGE > %s/index.html", string(dir))
 		c.RunCmdSync(m, cmd)
 
-		cmd = fmt.Sprintf("sudo podman run -d -p 80:80 -v %s/index.html:%s/index.html:z %s", string(dir), wwwRoot, image)
+		webServerCmd := fmt.Sprintf("sh -c 'dnf install -y python3 && python3 -m http.server -d %s 80'", wwwRoot)
+		cmd = fmt.Sprintf("sudo podman run -d -p 80:80 -v %s/index.html:%s/index.html:z %s %s", string(dir), wwwRoot, image, webServerCmd)
 		out := c.MustSSH(m, cmd)
 		id = string(out)[0:64]