Rename docs to doc to align with OpenStack standard

This patchset updates docs to doc to align with OpenStack
standard. Follow-up patchset will be needed to publish
documentation to OpenStack [0].

TODO: Update Armada documentation job to align with [1].

[0] https://docs.openstack.org/doc-contrib-guide/project-guides.html
[1] http://lists.openstack.org/pipermail/openstack-dev/2018-March/128594.html

Change-Id: I100541611ddfcd5c42f09da631346cb8ef3de5e7

.gitignore

@@ -65,8 +65,8 @@ instance/
 .scrapy
 
 # Sphinx documentation
-docs/build/
-docs/source/_static
+doc/build/
+doc/source/_static
 
 # PyBuilder
 target/

setup.cfg

@@ -27,8 +27,8 @@ packages =
     hapi.version
 
 [build_sphinx]
-source-dir = docs/source
-build-dir = docs/build
+source-dir = doc/source
+build-dir = doc/build
 all_files = 1
 warning-is-error = 1
 

tox.ini

@@ -56,4 +56,4 @@ commands =
 [flake8]
 filename = *.py
 ignore =
-exclude = .git,.tox,dist,*lib/python*,*egg,build,releasenotes,docs/*,hapi,venv
+exclude = .git,.tox,dist,*lib/python*,*egg,build,releasenotes,doc/*,hapi,venv