Fix Doc8 failure in OSSN-0047

Whitelist OSSN-0047, we need the long lines.

Move doc8 check to niceness check so that it's always run. The check is
also voting.

Closes-Bug: #1445599
Change-Id: Ie7af6c70a32cfcd0ecacc1bd05a63e9bc202aef9

tox.ini

@@ -22,12 +22,13 @@ commands = {posargs}
 commands = openstack-doc-test --check-links {posargs}
 
 [testenv:checkniceness]
-commands = openstack-doc-test --check-niceness {posargs}
+commands =
+     openstack-doc-test --check-niceness {posargs}
+     doc8 -e '' security-notes
 
 [testenv:checksyntax]
 commands =
     openstack-doc-test --check-syntax {posargs}
-    doc8 -e '' security-notes
     # Check that .po and .pot files are valid:
     bash -c "find security-guide -type f -regex '.*\.pot?' -print0|xargs -0 -n 1 msgfmt --check-format -o /dev/null"
 
@@ -40,7 +41,7 @@ commands = openstack-doc-test --check-build {posargs}
 [testenv:publishdocs]
 # Prepare all documents so that they can get published on
 # docs.openstack.org with just copying publish-docs/* over.
-commands = 
+commands =
   # Create directory, it might not be here if openstack-doc-test does
   # not publish anything.
   mkdir publish-docs
@@ -71,3 +72,7 @@ commands = doc-tools-check-languages doc-tools-check-languages.conf test {posarg
 sitepackages=True
 whitelist_externals = doc-tools-check-languages
 commands = doc-tools-check-languages doc-tools-check-languages.conf test all
+
+[doc8]
+# This file has extra long lines that cannot be avoided, let's white list it.
+ignore-path = security-notes/OSSN-0047