Monitoring IPMItool Bug fix

- The username and password for ipmitool command needs to be taken from configuration in server JSON
- If not configured, default credentials used will be admin/admin

Copy into 2.0 of Change-Id: I99c7d91dde512b1b54f24605a7a584e396690021

Change-Id: I2040f83a511647080c0ac4a9ba87fd94e96edc70