debootstrap: fix root build if no packages are installed

The current ebclfsa hi image does not install any packages (apart from the default ones).
Build fails, the implementation tries to unpack the non existing package_hash cache entry.
Instead the apt_hash entry has to eb unpacked

ebcl/tools/root/debootstrap.py

@@ -489,10 +489,12 @@ def build_debootstrap_image(self, name: str) -> Optional[str]:
         apt_hash = self._get_apt_hash(debootstrap_hash)
         package_hash = self._get_package_hash(apt_hash)
 
-        run_debootstrap = not (self._has_cache_archive(debootstrap_hash) or self._has_cache_archive(
-            apt_hash) or self._has_cache_archive(package_hash))
-        run_update = not (self._has_cache_archive(apt_hash)
-                          or self._has_cache_archive(package_hash))
+        run_debootstrap = not (
+            self._has_cache_archive(debootstrap_hash)
+            or self._has_cache_archive(apt_hash)
+            or self._has_cache_archive(package_hash)
+        )
+        run_update = not (self._has_cache_archive(apt_hash) or self._has_cache_archive(package_hash))
         run_packages = not self._has_cache_archive(package_hash)
 
         if run_debootstrap:
@@ -504,10 +506,13 @@ def build_debootstrap_image(self, name: str) -> Optional[str]:
             if not self._run_update(debootstrap_hash):
                 return None
 
-        if run_packages and self.config.packages:
-            self._extract_form_cache(apt_hash)
-            if not self._run_install_packages(apt_hash):
-                return None
+        if run_packages:
+            if self.config.packages:
+                self._extract_form_cache(apt_hash)
+                if not self._run_install_packages(apt_hash):
+                    return None
+                else:
+                    self._extract_form_cache(apt_hash)
         else:
             self._extract_form_cache(package_hash)