Include apache/_core.conf in wsgi template for Pike

This patch includes _core.conf template from Apache to make sure
keepalives are disabled for host when SSL is configured.

More info may be found here https://bugs.launchpad.net/devstack/+bug/1630664
And here https://review.openstack.org/#/c/433738/

Change-Id: Ie94c3969b573d0e24640de0898efbc9cc8690bee
1 file changed