stages/rpm: sort packages metadata

In order to have a more stable package metadata representation,
sort the generated metadata by name. Adapt the tests' metadata
file to reflect that change.

stages/org.osbuild.rpm

@@ -37,6 +37,7 @@ import pathlib
 import subprocess
 import sys
 import tempfile
+from operator import itemgetter
 
 from osbuild import api
 
@@ -162,7 +163,12 @@ def generate_package_metadata(tree):
 
     raw = res.stdout.strip()
     jsdata = '{"packages": [' + raw[:-1] + "]}"
-    return json.loads(jsdata)
+    data = json.loads(jsdata)
+
+    data["packages"] = sorted(data["packages"],
+                              key=itemgetter("name"))
+
+    return data
 
 
 def disable_dracut(tree):
@@ -254,7 +260,6 @@ def main(tree, inputs, options):
 
     subprocess.run(["/bin/sh", "-c", script], check=True)
 
-
     extra_args = []
 
     if options.get("exclude", {}).get("docs"):