Create structure for Devstack plugin

This adds the basic structure of the Devstack plugin. Required to
enable a gate which actually runs this plugin. Patch to follow that
sets up the and configures the mixmatch project in Devstack.

It also enable bashate in the pep8 job for the plugin.sh file.
Bashate is comparable to pep8, but for bash scripts.

Change-Id: I142def16a3179ec5cc390f419e2442dd3b93683c

devstack/plugin.sh

@@ -0,0 +1,44 @@
+# Copyright 2016 Massachusetts Open Cloud
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+# For more information on Devstack plugins, including a more detailed
+# explanation on when the different steps are executed please see:
+# http://docs.openstack.org/developer/devstack/plugins.html
+
+if [[ "$1" == "stack" && "$2" == "install" ]]; then
+    # This phase is executed after the projects have been installed
+    echo "Mix & match plugin - Install phase"
+
+elif [[ "$1" == "stack" && "$2" == "post-config" ]]; then
+    # This phase is executed after the projects have been configured and
+    # before they are started
+    echo "Mix & match plugin - Post-config phase"
+
+elif [[ "$1" == "stack" && "$2" == "extra" ]]; then
+    # This phase is executed after the projects have been started
+    echo "Mix & match plugin - Extra phase"
+
+fi
+
+if [[ "$1" == "unstack" ]]; then
+    # Called by unstack.sh and clean.sh
+    # Undo what was performed during the "post-config" and "extra" phases
+    :
+fi
+
+if [[ "$1" == "clean" ]]; then
+    # Called by clean.sh after the "unstack" phase
+    # Undo what was performed during the "install" phase
+    :
+fi

test-requirements.txt

@@ -7,6 +7,7 @@ testtools>=1.4.0 # MIT
 flake8<2.6.0,>=2.5.4 # MIT
 mock>=2.0 # BSD
 requests-mock>=1.1 # Apache-2.0
+bashate>=0.2 # Apache-2.0
 
 hacking<0.12,>=0.11.0 # Apache-2.0
 

tox.ini

@@ -13,7 +13,9 @@ deps = -r{toxinidir}/test-requirements.txt
 commands = python setup.py test --slowest --testr-args='{posargs}'
 
 [testenv:pep8]
-commands = flake8 {posargs}
+commands =
+  flake8 {posargs}
+  bashate devstack/plugin.sh
 
 [testenv:venv]
 commands = {posargs}