Remove preference for dnf4 in mkosi-initrd

This effectively reverts 7b92904 as DNF 5 is now the new default
in the most recent Fedora release.

mkosi/initrd.py

@@ -14,7 +14,7 @@
 from mkosi.config import DocFormat, OutputFormat
 from mkosi.documentation import show_docs
 from mkosi.log import log_notice, log_setup
-from mkosi.run import find_binary, run, uncaught_exception_handler
+from mkosi.run import run, uncaught_exception_handler
 from mkosi.sandbox import __version__, umask
 from mkosi.tree import copy_tree
 from mkosi.types import PathString
@@ -200,13 +200,10 @@ def main() -> None:
         if Path("/etc/kernel/cmdline").exists():
             cmdline += ["--kernel-command-line", Path("/etc/kernel/cmdline").read_text()]
 
-        # Prefer dnf as dnf5 has not yet officially replaced it and there's a much bigger chance that there
-        # will be a populated dnf cache directory.
         run(
             cmdline,
             stdin=sys.stdin,
             stdout=sys.stdout,
-            env={"MKOSI_DNF": dnf.name} if (dnf := find_binary("dnf", "dnf5")) else {},
         )
 
         if args.output_dir: