bios: Don't bail out if grub2-install is not present

Instead of making it a fatal error, just make the component to be skipped.

This allows to generate the update metadata for other components, instead
of failing due not being able to generate the metadata for BIOS component.

Author: martinezjavier

src/bios.rs

@@ -130,7 +130,8 @@ impl Component for Bios {
     fn generate_update_metadata(&self, sysroot_path: &str) -> Result<Option<ContentMetadata>> {
         let grub_install = Path::new(sysroot_path).join(GRUB_BIN);
         if !grub_install.exists() {
-            bail!("Failed to find {:?}", grub_install);
+            println!("Failed to find {:?}", grub_install);
+            return Ok(None);
         }
 
         // Query the rpm database and list the package and build times for /usr/sbin/grub2-install