Add /usr/local/bin to cinders rootwrap.conf

TripleO source installs require /usr/local/bin to be a valid
rootwrap patch. This is to support cinder-rtstool access when
using cinder-lio.

Without this patch all cinder-rtstool commands fail...

Change-Id: Ida0b73c68ea766b0456874bc01ee8b33f79408e0
Merge "Add /usr/local/bin to cinders rootwrap.conf"