Fix doc8 check failures

Resolves D000 and D001 checks in sahara docs.

Change-Id: If6d577859170ae55d578d70885a9ed5a6b0db651
Closes-Bug: #1514887

tox.ini

@@ -41,18 +41,13 @@ downloadcache = ~/cache/pip
 [testenv:pep8]
 commands =
     flake8 {posargs}
+    doc8 doc/source
     # Check that .po and .pot files are valid:
     bash -c "find sahara -type f -regex '.*\.pot?' -print0|xargs -0 -n 1 msgfmt --check-format -o /dev/null"
     # Run bashate checks
     bash -c "find sahara -iname '*.sh' -print0 | xargs -0 bashate -v"
     bash -c "find devstack -not -name README.rst -and -not -name \*.json -type f -print0 | xargs -0 bashate -v"
 
-[testenv:doc8]
-deps =
-    -r{toxinidir}/requirements.txt
-    -r{toxinidir}/test-requirements.txt
-commands = doc8 doc/source
-
 [testenv:venv]
 commands = {posargs}