Fix senlin gate job
Senlin gate job is broken for local configuration generated
in pre_test_hook is not kept. This patch fixes this issue.
export PYTHONUNBUFFERED=true
export BRANCH_OVERRIDE={branch-override}
export PROJECTS="openstack/senlin $PROJECTS"
+ export KEEP_LOCALRC=1
export DEVSTACK_GATE_TEMPEST=1
export DEVSTACK_GATE_TEMPEST_ALL_PLUGINS=1
export DEVSTACK_GATE_TEMPEST_REGEX="senlin.tests.tempest.{test_type}"
