Merging in latest boto.

boto/ec2/spotpricehistory.py

Index: boto/ec2/spotpricehistory.py
diff --git a/boto/ec2/spotpricehistory.py b/boto/ec2/spotpricehistory.py
index d4e171102bd8b9b0f6b8a2a2f47a1c9e53bcc732..268d6b35a6c06adc25e45d93030f5ab0f1fc9c65 100644
--- a/boto/ec2/spotpricehistory.py
+++ b/boto/ec2/spotpricehistory.py
@@ -33,6 +33,7 @@ class SpotPriceHistory(EC2Object):
         self.instance_type = None
         self.product_description = None
         self.timestamp = None
+        self.availability_zone = None
 
     def __repr__(self):
         return 'SpotPriceHistory(%s):%2f' % (self.instance_type, self.price)
@@ -46,6 +47,8 @@ class SpotPriceHistory(EC2Object):
             self.product_description = value
         elif name == 'timestamp':
             self.timestamp = value
+        elif name == 'availabilityZone':
+            self.availability_zone = value
         else:
             setattr(self, name, value)