Create linters test target

Merge bashate and pep8 into a single linters test environment.

Change-Id: I13c68da7cb69fe240179a2074512decbf2a35560

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 1.6
-envlist = pep8
+envlist = linters
 skipsdist = True
 
 [testenv]
@@ -8,6 +8,11 @@ usedevelop = True
 install_command = pip install {opts} {packages}
 deps = -r{toxinidir}/test-requirements.txt
 
+[testenv:linters]
+commands =
+  flake8
+  {toxinidir}/tools/run-bashate.sh
+
 [testenv:pep8]
 commands = flake8