Sync Sphinx requirement

1. Sync sphinx dependency with global requirements. It caps python 2 since
sphinx 2.0 no longer supports Python 2.7.
2. Update some URLs to latest

Change-Id: I3609e926808563b031c0e50d898515f1c9109e72
Closes-Bug: #1831525

HACKING.rst

@@ -55,6 +55,6 @@ Manual tests:
 OpenStack Style Commandments
 ============================
 
-- Step 1: Read http://www.python.org/dev/peps/pep-0008/
-- Step 2: Read http://www.python.org/dev/peps/pep-0008/ again
-- Step 3: Read https://github.com/openstack-dev/hacking/blob/master/HACKING.rst
+- Step 1: Read https://www.python.org/dev/peps/pep-0008/
+- Step 2: Read https://www.python.org/dev/peps/pep-0008/ again
+- Step 3: Read https://github.com/openstack/hacking/blob/master/HACKING.rst

test-requirements.txt

@@ -15,5 +15,6 @@ xvfbwrapper>=0.1.3 #license: MIT
 
 # Doc requirements
 openstackdocstheme>=1.18.1 # Apache-2.0
-sphinx!=1.6.6,!=1.6.7,>=1.6.2 # BSD
+sphinx!=1.6.6,!=1.6.7,>=1.6.2,<2.0.0;python_version=='2.7'  # BSD
+sphinx!=1.6.6,!=1.6.7,>=1.6.2;python_version>='3.4'  # BSD
 reno>=2.5.0 # Apache-2.0

watcher_dashboard/test/integration_tests/horizon.conf

@@ -7,7 +7,7 @@
 dashboard_url=http://localhost:8000/
 
 # Dashboard help page url (string value)
-help_url=http://docs.openstack.org/
+help_url=https://docs.openstack.org/
 
 [selenium]
 # Timeout in seconds to wait for a page to become available