efi: install grub.cfg under new vendor during updates

When doing switches from RHEL 10 to Fedora 43, after reboot, check
grub.cfg and bootuuid.cfg are in old vendor redhat, that will make
the machine fails to boot a second time since grub.cfg cannot be
found.

We need to install the 2 files under new vendor during updates.

See #1024

Author: HuijingHei

src/efi.rs

@@ -481,14 +481,42 @@ impl Component for Efi {
             anyhow::bail!("Failed to find all esp devices");
         };
 
+        // Get old vendor name from installed filetree
+        let old_vendor = {
+            let mut vendor = "";
+            for child in currentf.children.keys() {
+                if child.ends_with(SHIM) {
+                    vendor = child.strip_suffix(&format!("/{SHIM}")).unwrap_or("");
+                    break;
+                }
+            }
+            vendor.to_owned()
+        };
+
         for esp in esp_devices {
             let destpath = &self.ensure_mounted_esp(rootcxt.path.as_ref(), Path::new(&esp))?;
-            let destdir = openat::Dir::open(&destpath.join("EFI")).context("opening EFI dir")?;
+            let dest_efi = destpath.join("EFI");
+            let destdir = openat::Dir::open(&dest_efi).context("opening EFI dir")?;
             validate_esp_fstype(&destdir)?;
+
             log::trace!("applying diff: {}", &diff);
             filetree::apply_diff(&updated, &destdir, &diff, None)
                 .context("applying filesystem changes")?;
 
+            // Install grub.cfg under new vendor
+            {
+                // Get new vendor name
+                let sysroot = rootcxt.path.as_std_path();
+                let Some(new_vendor) = self.get_efi_vendor(&sysroot.join(&updated_path))? else {
+                    anyhow::bail!("Failed to find efi vendor in new update");
+                };
+                if new_vendor != old_vendor && destdir.exists(&old_vendor)? {
+                    grubconfigs::install(sysroot_dir, None, Some(&new_vendor), true)?;
+                    destdir.remove_all(&old_vendor)?;
+                    assert!(destdir.exists(format!("{new_vendor}/{}", grubconfigs::GRUBCONFIG))?);
+                }
+            }
+
             // Do the sync before unmount
             fsfreeze_thaw_cycle(destdir.open_file(".")?)?;
             drop(destdir);
@@ -609,7 +637,7 @@ impl Component for Efi {
 
         // Does not support multiple shim for efi
         if shim_files.len() > 1 {
-            anyhow::bail!("Found multiple {SHIM} in the image");
+            anyhow::bail!("Found multiple {SHIM} in the image: {:?}", shim_files);
         }
         if let Some(p) = shim_files.first() {
             let p = p