Convert OpenRC to a centralized copyright/license structure

In the past, OpenRC was a hybrid of a centralized and file-scope
license/copyright structure.

I followed the instructions from the Software Freedom Law Center [1] to
convert to a Centralized structure where possible, for easier future
maintenance.

[1] https://softwarefreedom.org/resources/2012/ManagingCopyrightInformation.html

scripts/on_ac_power

@@ -1,8 +1,17 @@
 #!/bin/sh
 # Detect AC power or not in a portable way
-# Copyright (c) 2007-2009 Roy Marples <roy@marples.name>
-
 # Exit 0 if on AC power, 1 if not and 255 if we don't know how to work it out
+
+# Copyright (c) 2007-2015 The OpenRC Authors.
+# See the Authors file at the top-level directory of this distribution and
+# https://github.com/OpenRC/openrc/blob/master/AUTHORS
+#
+# This file is part of OpenRC. It is subject to the license terms in
+# the LICENSE file found in the top-level directory of this
+# distribution and at https://github.com/OpenRC/openrc/blob/master/LICENSE
+# This file may not be copied, modified, propagated, or distributed
+#    except according to the terms contained in the LICENSE file.
+
 if [ -f /proc/acpi/ac_adapter/*/state ]; then
 	cat /proc/acpi/ac_adapter/*/state | while read line; do
 		case "$line" in

scripts/rc-sstat.in

@@ -1,4 +1,13 @@
 #!@SHELL@
+# Copyright (c) 2015 The OpenRC Authors.
+# See the Authors file at the top-level directory of this distribution and
+# https://github.com/OpenRC/openrc/blob/master/AUTHORS
+#
+# This file is part of OpenRC. It is subject to the license terms in
+# the LICENSE file found in the top-level directory of this
+# distribution and at https://github.com/OpenRC/openrc/blob/master/LICENSE
+# This file may not be copied, modified, propagated, or distributed
+#    except according to the terms contained in the LICENSE file.
 
 # Define variables
 scandir="/run/openrc/s6-scan"