Correct getchildren() usage in list_addresses()

This commit fixes the usage of getchildren in the list_addresses
method. Previously, the method was called on body which was a string.
This commit corrects the behavior and runs the method on an etree
object.

Fixes bug 1132796

Change-Id: Iafb8d51257b7bcbfbcf9141c3d424c601a186a89
Merge "Correct getchildren() usage in list_addresses()"