Use https for links

Use https instead of http when link to docs.openstack.org.

Change-Id: Iaf643a1c110aac53cd036537a583d58eebbf817d
diff --git a/setup.cfg b/setup.cfg
index 86ffa5a..24207d0 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -5,7 +5,7 @@
     README.rst
 author = OpenStack Infrastructure Team
 author-email = openstack-infra@lists.openstack.org
-home-page = http://docs.openstack.org/infra/system-config/
+home-page = https://docs.openstack.org/infra/system-config/
 classifier =
     Intended Audience :: Information Technology
     Intended Audience :: System Administrators