[PATCH] portupgrade, get_all_depends method crashes

[KISHIMOTO, Makoto]

Hello,

In portupgrade, get_all_depends method crashes if portdir not found.
(for example http://www.freebsd.org/cgi/query-pr.cgi?pr=140192 )

following patch is workaround.

--- portupgrade.ORG	2009-12-20 10:11:00.000000000 +0900
+++ portupgrade	2009-12-20 10:16:10.000000000 +0900
@@ -834,7 +834,7 @@
     depends = Set.new
 
     portdir = $portsdb.portdir(origin)
-    return nil if not File.directory?(portdir)
+    return [] if not File.directory?(portdir)
 
     begin
       run_make_config(portdir, origin) if $config