[interchange] Fixed typo in Cart.pm

[Jon Jensen]

commit ef98436a6ab91034b4750032d4a7e6f349866b17
Author: Josh Lavin <josh at perusion.com>
Date:   Mon Oct 4 11:57:39 2010 -0500

    Fixed typo in Cart.pm
    
    Happened to prevent MaxQuantityField from working for a value of 0

 lib/Vend/Cart.pm |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/lib/Vend/Cart.pm b/lib/Vend/Cart.pm
index 88bf42c..4eb01eb 100644
--- a/lib/Vend/Cart.pm
+++ b/lib/Vend/Cart.pm
@@ -275,7 +275,7 @@ sub toss_cart {
 				  last MAX_QUANTITY;
 			      }
 
-			      elsif ($prefix = '?') {
+			      elsif ($prefix eq '?') {
 				  next QUANTITY_FIELD if !defined $$max || $$max <= 0;
 				  $$mv_max = $$max;
 				  last QUANTITY_ADJUST;