Remove tools/run_cross_tests.sh from openstack-common.conf
Remove tools/run_cross_tests.sh from openstack-common.conf

This script is no longer in the oslo-incubator repo

Change-Id: Icc901057bae58eb01de096e17ce2baaf97789cf2

openstack/oslo.concurrency,varunarya10/oslo.concurrency,JioCloud/oslo.concurrency