Allow getHeatStackServers method to find nested servers

Currently getHeatStackServers method is broken.

This patch fixes it by fixing typo in getHeatStackResourceInfo call
Also this patch adds method for finding servers in all nested stacks,
depth is set to 1000 to make sure we can get very big nested stacks.

Change-Id: Idd948050d3f9fd93ef4ed218aa1d70ef8a7c189e
Related-Prod: PROD-17558
1 file changed