[libgee] Fix Traversable.chop method, fixes bug #684348

[Maciej Marcin Piechotka <mpiechotka src gnome org>]

commit 773b1fb0cd6e047022353dc7cc55ae3e4355f485
Author: Maciej Piechotka <uzytkownik2 gmail com>
Date:   Thu Sep 20 21:05:49 2012 -0700

    Fix Traversable.chop method, fixes bug #684348

 gee/traversable.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gee/traversable.vala b/gee/traversable.vala
index ac757c5..9c8a183 100644
--- a/gee/traversable.vala
+++ b/gee/traversable.vala
@@ -338,7 +338,6 @@ public interface Gee.Traversable<G> : Object {
 				if (offset > 0) {
 					return Stream.CONTINUE;
 				} else if (length > 0) {
-					length--;
 					return length != 0 ? Stream.CONTINUE : Stream.END;
 				} else if (length == 0) {
 					return Stream.END;
@@ -348,6 +347,7 @@ public interface Gee.Traversable<G> : Object {
 			case Stream.CONTINUE:
 				if (offset == 0) {
 					val = item;
+					length--;
 					return Stream.YIELD;
 				} else {
 					val = null;