The build_list_parameters function only contains half of the fix applied by upstream
commit 79f6a6cc7b2420440091. Specifically, line 78 refers to a function parameter that
was renamed. More details at: https://bugzilla.redhat.com/show_bug.cgi?id=647005

--- boto-1.9b/boto/ec2/blockdevicemapping.py		2009-12-16 17:21:40.000000000 +0100
+++ boto-1.9b/boto/ec2/blockdevicemapping.py.prefix	2010-11-18 21:59:07.000000000 +0100
@@ -75,7 +75,7 @@
     def build_list_params(self, params, prefix=''):
         i = 1
         for dev_name in self:
-            pre = '%sBlockDeviceMapping.%d' % (pre, i)
+            pre = '%sBlockDeviceMapping.%d' % (prefix, i)
             params['%s.DeviceName' % pre] = dev_name
             ebs = self[dev_name]
             if ebs.snapshot_id: