Fix i18n issue for nova/virt/baremetal/virtual_power_driver.py

There are some log messages in virtual_power_driver.py does not
support i18n, we need to update code to support it.

Closes-bug: #1228449

Change-Id: I6642309bd0e08e356a13d134ac0c743159af2520
Merge "Fix i18n issue for nova/virt/baremetal/virtual_power_driver.py"