fix lingering references to /var/lib/{backlight,random-seed}

This should have been part of ef5bfcf668.

man/systemd-backlight@.service.xml

@@ -58,7 +58,7 @@
                 is a service that restores the display backlight
                 brightness at early-boot and saves it at shutdown. On
                 disk, the backlight brightness is stored in
-                <filename>/var/lib/backlight/</filename>. Note that by
+                <filename>/var/lib/systemd/backlight/</filename>. Note that by
                 default, only firmware backlight devices are
                 saved/restored.</para>
         </refsect1>

man/systemd-random-seed.service.xml

@@ -61,7 +61,7 @@
                 for details. Saving/restoring the random seed across
                 boots increases the amount of available entropy early
                 at boot. On disk the random seed is stored in
-                <filename>/var/lib/random-seed</filename>.</para>
+                <filename>/var/lib/systemd/random-seed</filename>.</para>
         </refsect1>
 
         <refsect1>

units/systemd-backlight@.service.in

@@ -9,7 +9,7 @@
 Description=Load/Save Screen Backlight Brightness of %I
 Documentation=man:systemd-backlight@.service(8)
 DefaultDependencies=no
-RequiresMountsFor=/var/lib/backlight
+RequiresMountsFor=/var/lib/systemd/backlight
 Conflicts=shutdown.target
 After=systemd-readahead-collect.service systemd-readahead-replay.service systemd-remount-fs.service
 Before=sysinit.target shutdown.target