Correct log message inside openstack module
Correct log message inside openstack module

Corrected log message for scale_wait method. Log message was not
logged properly because the format specifiers were not specified
correctly.

Change-Id: Ie0c84ffff19d3cc8511167cb949c98bf13d0fe16

openstack/tacker,openstack/tacker,stackforge/tacker,openstack/tacker,stackforge/tacker