Add manifest file to include base alembic config

This commit adds a manifset file to ensure that the base alembic
config file is installed in the correct path. The
subunit2sql-db-manage utility depends on that file exisiting in the
same dir so it can use it to build on based on the subunit2sql config
file.

Change-Id: Icc0d97ca1d1b0bd91434a38014902b922a4ff3ba

MANIFEST.in

@@ -0,0 +1,6 @@
+include subunit2sql/migrations/alembic.ini
+
+exclude .gitreview
+exclude .gitignore
+
+global-exclude *.pyc

setup.cfg

@@ -20,6 +20,10 @@ classifier =
 packages =
     subunit2sql
 
+[global]
+setup-hooks =
+    pbr.hooks.setup_hook
+
 [entry_points]
 console_scripts =
     subunit2sql = subunit2sql.shell:main