Use flask manage for all versions

The legacy method does not work any longer, so just use the Flask manage
script and remove the obsolete legacy one.

api-daemon/pvc-api-db-upgrade

@@ -12,16 +12,7 @@ fi
 
 pushd /usr/share/pvc
 
-case "$( cat /etc/debian_version )" in
-    10.*|11.*)
-        # Debian 10 & 11
-        ./pvcapid-manage_legacy.py db upgrade
-    ;;
-    *)
-        # Debian 12+
-        export FLASK_APP=./pvcapid-manage_flask.py
+export FLASK_APP=./pvcapid-manage-flask.py
 flask db upgrade
-    ;;
-esac
 
 popd

api-daemon/pvcapid-manage_legacy.py

@@ -1,33 +0,0 @@
-#!/usr/bin/env python3
-
-# pvcapid-manage_legacy.py - PVC Database management tasks (Legacy)
-# Part of the Parallel Virtual Cluster (PVC) system
-#
-#    Copyright (C) 2018-2024 Joshua M. Boniface <joshua@boniface.me>
-#
-#    This program is free software: you can redistribute it and/or modify
-#    it under the terms of the GNU General Public License as published by
-#    the Free Software Foundation, version 3.
-#
-#    This program is distributed in the hope that it will be useful,
-#    but WITHOUT ANY WARRANTY; without even the implied warranty of
-#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-#    GNU General Public License for more details.
-#
-#    You should have received a copy of the GNU General Public License
-#    along with this program.  If not, see <https://www.gnu.org/licenses/>.
-#
-###############################################################################
-
-from flask_migrate import Migrate, MigrateCommand, Manager
-
-from pvcapid.flaskapi import app, db
-from pvcapid.models import *  # noqa F401,F403
-
-migrate = Migrate(app, db)
-manager = Manager(app)
-
-manager.add_command("db", MigrateCommand)
-
-if __name__ == "__main__":
-    manager.run()