Update log message for scale out/in

When create two stacks with same template with autoscaling group,
then when scale out/in, the log message would be as
(HadoopSlaveScaleUpPolicy is my scale up alarm and HadoopSGroup is
my autoscaling group):

HadoopSlaveScaleUpPolicy Alarm, adjusting Group HadoopSGroup by 1

From above log message, I do not know which stack is being scaled up.

This patch add scale group id to the log message so that we can know
which group is being scale out/in.

Change-Id: Ie4862e9738c652b813b3dae01f9aeb3557e79b9a
Closes-Bug: #1265315
Merge "Update log message for scale out/in"