agent: Add CreateContainer support for pre-pulled bundle

- Add a check in setup_bundle to see if the bundle already exists
and if it does then skip the setup.

This commit is cherry-picked from 44ed3ab80e.

The reason that k8s-kill-all-process-in-container.bats failed is that
deletion of the directory `/root/kata-containers/cid/rootfs` failed during removing container
because it was mounted twice (one in image-rs and one in set_bundle ) and only unmounted once in removing container.

Fixes: #9664

Signed-off-by: ChengyuZhu6 <chengyu.zhu@intel.com>
Co-authored-by: Dave Hay <david_hay@uk.ibm.com>
Signed-off-by: stevenhorsman <steven@uk.ibm.com>

src/agent/src/rpc.rs

@@ -1926,15 +1926,23 @@ pub fn setup_bundle(cid: &str, spec: &mut Spec) -> Result<PathBuf> {
     let config_path = bundle_path.join("config.json");
     let rootfs_path = bundle_path.join("rootfs");
 
-    fs::create_dir_all(&rootfs_path)?;
-    baremount(
-        spec_root_path,
-        &rootfs_path,
-        "bind",
-        MsFlags::MS_BIND,
-        "",
-        &sl(),
-    )?;
+    let rootfs_exists = Path::new(&rootfs_path).exists();
+    info!(
+        sl(),
+        "The rootfs_path is {:?} and exists: {}", rootfs_path, rootfs_exists
+    );
+
+    if !rootfs_exists {
+        fs::create_dir_all(&rootfs_path)?;
+        baremount(
+            spec_root_path,
+            &rootfs_path,
+            "bind",
+            MsFlags::MS_BIND,
+            "",
+            &sl(),
+        )?;
+    }
 
     let rootfs_path_name = rootfs_path
         .to_str()