tox: generate sample config file on default target

This will make sure we don't break the config generator in the future –
same technique we use in Gnocchi.

Change-Id: Ia20f3c3e8d3772d5eeec679002cf7eb03c34570d

generate-config-file.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+oslo-config-generator --output-file etc/aodh/aodh.conf \
+                      --namespace aodh \
+                      --namespace oslo.db \
+                      --namespace oslo.log \
+                      --namespace oslo.messaging \
+                      --namespace oslo.policy \
+                      --namespace oslo.service.service \
+                      --namespace keystonemiddleware.auth_token

tox.ini

@@ -14,6 +14,7 @@ commands =
    bash -x {toxinidir}/setup-test-env-mongodb.sh python setup.py testr --slowest --testr-args="{posargs}"
    bash -x {toxinidir}/setup-test-env-mysql.sh python setup.py testr --slowest --testr-args="{posargs}"
    bash -x {toxinidir}/setup-test-env-postgresql.sh python setup.py testr --slowest --testr-args="{posargs}"
+   {toxinidir}/generate-config-file.sh
 whitelist_externals = bash
 
 # TODO(ityaptin): With separation tests to unit and functional folders we need
@@ -61,15 +62,7 @@ commands =
     bash -c "find aodh -type f -regex '.*\.pot?' -print0|xargs -0 -n 1 msgfmt --check-format -o /dev/null"
 
 [testenv:genconfig]
-commands =
-    oslo-config-generator --output-file etc/aodh/aodh.conf \
-    --namespace aodh \
-    --namespace oslo.db \
-    --namespace oslo.log \
-    --namespace oslo.messaging \
-    --namespace oslo.policy \
-    --namespace oslo.service.service \
-    --namespace keystonemiddleware.auth_token
+commands = {toxinidir}/generate-config-file.sh
 
 [testenv:docs]
 commands = python setup.py build_sphinx