shorten copyright header of configuration files

units/sys-kernel-debug.mount

@@ -1,19 +1,9 @@
 #  This file is part of systemd.
 #
-#  Copyright 2010 Lennart Poettering
-#
 #  systemd 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; either version 2 of the License, or
 #  (at your option) any later version.
-#
-#  systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
 
 [Unit]
 Description=Debug File System