[dracut] add asked for schema.yaml

corrected if statement

src/modules/dracut/dracut.schema.yaml

+# SPDX-FileCopyrightText: 2022 Anke Boersma <demm@kaosx.us>
+# SPDX-License-Identifier: GPL-3.0-or-later
+---
+$schema: https://json-schema.org/schema#
+$id: https://calamares.io/schemas/dracut
+additionalProperties: false
+type: object
+properties:
+    kernelName: { type: string }

src/modules/dracut/main.py

@@ -36,10 +36,10 @@ def run_dracut():
     """
     kernelName = libcalamares.job.configuration['kernelName']
 
-    if kernelName != 0:
-        return check_target_env_call(['dracut', '-f', '{}'.format(kernelName)])
-    else:
+    if not kernelName:
         return check_target_env_call(['dracut', '-f'])
+    else:
+        return check_target_env_call(['dracut', '-f', '{}'.format(kernelName)])
 
 
 def run():