Add bashate tox command

Now that we copied the devstack code to our tree we need to ensure that
the bash scripts we have are correct. This patch is adding a tox command
(bashate) that will check the syntax of the shell scripts under
the devstack/ directory.

The scripts under devstack/tools/ are not being checked, that's because
they weren't check when the code was in devstack as well and there's
loads to fix. It will be fixed in a following patch.

Change-Id: I8f66492081e0fd10e1de057febb9324a81411c7a
Partial-Bug: #1526518

tox.ini

@@ -1,7 +1,7 @@
 [tox]
 minversion = 1.8
 skipsdist = True
-envlist = py34,py27,pep8
+envlist = py34,py27,pep8,bashate
 
 [testenv]
 usedevelop = True
@@ -62,6 +62,24 @@ commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasen
 setenv = PYTHONHASHSEED=0
 commands = {posargs}
 
+[testenv:bashate]
+deps =
+   {env:BASHATE_INSTALL_PATH:bashate==0.3.2}
+whitelist_externals = bash
+# TODO(lucasagomes): Check the tools/ directory as well
+commands = bash -c "find {toxinidir}/devstack    \
+         -not \( -type d -name .?\* -prune \)    \ # prune all 'dot' dirs
+         -type f                                 \ # only files
+         -not -name \*.swp                       \ # skip editor files
+         -not -name \*~                          \ # skip editor files
+         -not -name \*.xml                       \ # skip xml files
+         -not -name \*.template                  \ # skip template files
+         \(                                      \
+          -name \*.sh -or                        \ # add files eding with .sh
+          -wholename \*/lib/\*                   \ # add files under lib/
+         \)                                      \
+         -print0 | xargs -0 bashate -v -iE006 -eE005,E042"
+
 [flake8]
 ignore = E129
 exclude =  .venv,.git,.tox,dist,doc,*openstack/common*,*lib/python*,*egg,build,tools