udev rules and manpages in section 8 were installed into $out/usr

Results in the following derivation output diff:

 lib/systemd/system
 lib/systemd/system/multipathd.service
 lib/systemd/system/multipathd.socket
+lib/udev
+lib/udev/kpartx_id
+lib/udev/rules.d
+lib/udev/rules.d/11-dm-mpath.rules
+lib/udev/rules.d/11-dm-parts.rules
+lib/udev/rules.d/56-multipath.rules
+lib/udev/rules.d/66-kpartx.rules
+lib/udev/rules.d/68-del-part-nodes.rules
 sbin
 share
 share/man
@@ -79,25 +87,14 @@
 share/man/man3/mpath_persistent_reserve_out.3.gz
 share/man/man5
 share/man/man5/multipath.conf.5.gz
+share/man/man8
+share/man/man8/kpartx.8.gz
+share/man/man8/mpathpersist.8.gz
+share/man/man8/multipath.8.gz
+share/man/man8/multipathd.8.gz
 usr
 usr/include
 usr/include/libdmmp
 usr/include/libdmmp/libdmmp.h
 usr/include/mpath_cmd.h
 usr/include/mpath_persist.h
-usr/lib
-usr/lib/udev
-usr/lib/udev/kpartx_id
-usr/lib/udev/rules.d
-usr/lib/udev/rules.d/11-dm-mpath.rules
-usr/lib/udev/rules.d/11-dm-parts.rules
-usr/lib/udev/rules.d/56-multipath.rules
-usr/lib/udev/rules.d/66-kpartx.rules
-usr/lib/udev/rules.d/68-del-part-nodes.rules
-usr/share
-usr/share/man
-usr/share/man/man8
-usr/share/man/man8/kpartx.8.gz
-usr/share/man/man8/mpathpersist.8.gz
-usr/share/man/man8/multipath.8.gz
-usr/share/man/man8/multipathd.8.gz

multipath-tools: Fix prefix