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: I2ab509a8430cb3e7d297bd4303a492c21d59a7f3

doc/requirements.txt

@@ -1,4 +1,9 @@
-sphinx>=1.6.2,!=1.6.6,!=1.6.7 # BSD
+# The order of packages is significant, because pip processes them in the order
+# of appearance. Changing the order has an impact on the overall integration
+# process, which may cause wedges in the gate later.
+
+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
 sphinxcontrib-httpdomain>=1.3.0 # BSD
 sphinxcontrib-pecanwsme>=0.2 # Apache-2.0
 sphinxcontrib-seqdiag>=0.8.4 # BSD

doc/source/conf.py

@@ -98,4 +98,4 @@ latex_documents = [
 ]
 
 # Example configuration for intersphinx: refer to the Python standard library.
-#intersphinx_mapping = {'http://docs.python.org/': None}
+#intersphinx_mapping = {'https://docs.python.org/': None}

releasenotes/source/conf.py

@@ -87,7 +87,7 @@ html_last_updated_fmt = '%Y-%m-%d %H:%M'
 # to template names.
 #
 # This is required for the alabaster theme
-# refs: http://alabaster.readthedocs.io/en/latest/installation.html#sidebars
+# refs: https://alabaster.readthedocs.io/en/latest/installation.html#sidebars
 # html_sidebars = {}