Add chgrp --reference value completion.

CHANGES

@@ -36,6 +36,7 @@ bash-completion (1.x)
     take arguments in both "--foo bar" and "--foo=bar" formats.
   * Use _split_longopt to improve and clean up aspell, chgrp, chown completion.
   * Add chown --from and --reference value completions.
+  * Add chgrp --reference value completion.
 
   [ Todd Zullinger ]
   * Make yum complete on filenames after install, deplist, update and upgrade

bash_completion

@@ -843,6 +843,11 @@ _chgrp()
 
 	_split_longopt && split=true
 
+	if [[ "$prev" == --reference ]]; then
+		_filedir
+		return 0
+	fi
+
 	$split && return 0
 		
 	# options completion