boto/boto — pull request #1476 by znewman01 (2013-05-03 20:33:11+00:00)
Title: Add cancel_update_stack method to CloudFormation

Amazon has an action in the CloudFormation API called CancelUpdateStack
that rolls back a stack in the UPDATE_IN_PROGRESS state. This change
introduces a method to execute this action to the
cloudformation.connection.CloudFormationConnection class, based off of
the delete_stack method.