test/e2e: do not use /tmp for podman commands

Using the OS tempdir here is not good. This defaults to /tmp which means
the inital podman test setup uses these paths:
`--root /tmp/root --runroot /tmp/runroot and --tmpdir /tmp`

Thus we create many files directly under /tmp. Also they were never
removed thus leaked out. When running as root and then later as rooltess
this would fail to permission problems.

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

test/e2e/common_test.go

@@ -137,7 +137,7 @@ var _ = SynchronizedBeforeSuite(func() []byte {
 	// Cache images
 	cwd, _ := os.Getwd()
 	INTEGRATION_ROOT = filepath.Join(cwd, "../../")
-	podman := PodmanTestSetup(os.TempDir())
+	podman := PodmanTestSetup(GinkgoT().TempDir())
 
 	// Pull cirros but don't put it into the cache
 	pullImages := []string{CIRROS_IMAGE, fedoraToolbox, volumeTest}
@@ -180,6 +180,9 @@ var _ = SynchronizedBeforeSuite(func() []byte {
 		podman.StopRemoteService()
 	}
 
+	// remove temporary podman files, images are now cached in ImageCacheDir
+	podman.removeCache(podman.TempDir)
+
 	return []byte(path)
 }, func(data []byte) {
 	cwd, _ := os.Getwd()