Fix a mistake in tacker localrc
Fix a mistake in tacker localrc

missing '\n' in DEVSTACK_LOCAL_CONFIG line
Refer to https://review.openstack.org/#/c/471780/ for more info.

Change-Id: I81f6fa99c9528943a485b320f223235aa3ea5ec9

openstack-infra/project-config,openstack-infra/project-config