match Usage filters from PLD Linux initscripts
sample initscript template can be found from here:

http://svn.pld-linux.org/cgi-bin/viewsvn/rc-scripts/trunk/rc.d/init.d/template.init?rev=HEAD&view=log

--
Signed-off-by: Elan Ruusamäe <glen@delfi.ee>

--- bash-completion-1.0/bash_completion~	2009-05-12 12:05:37.000000000 +0300
+++ bash-completion-1.0/bash_completion	2009-05-12 12:07:58.771759678 +0300
@@ -751,7 +751,7 @@
 		_services
 	else
 		COMPREPLY=( $( compgen -W '`sed -ne "y/|/ /; \
-				s/^.*Usage.*{\(.*\)}.*$/\1/p" \
+				s/^.*\(U\|msg_u\)sage.*{\(.*\)}.*$/\2/p" \
 				$sysvdir/${prev##*/} 2>/dev/null`' -- $cur ) )
 	fi