Remove duplicate copyright.
Remove duplicate copyright.

This patch removes duplicate copyright string from
ironic/conf/ipmi.py

Change-Id: I966d6a498af3647d54e944015824f63594d41219

pshchelo/ironic,NaohiroTamura/ironic,openstack/ironic,NaohiroTamura/ironic,SauloAislan/ironic,openstack/ironic,pshchelo/ironic,SauloAislan/ironic