Add bashate test environment for shell scripts

Change-Id: I4cd71515b1f59552effbbca5fd01ad8174c45e34

tox.ini

@@ -0,0 +1,15 @@
+[tox]
+minversion = 1.6
+skipsdist = True
+envlist = bashate
+
+[testenv:bashate]
+deps = bashate
+whitelist_externals = bash
+commands = bash -c "find {toxinidir}          \
+         -not \( -type d -name .?\* -prune \) \
+         -type f                              \
+         -not -name \*~                       \
+         -not -name \*.md                     \
+         -name \*.sh                          \
+         -print0 | xargs -0 bashate -v"