Make kolla-build able to build source images

The pip installed kolla-build script was not able to build source images
due to missing build.ini file containing information where to download
sources.

Change-Id: Ibc347daff76b445f032d8366bea3a58549cda766
Closes-Bug: #1493728

setup.cfg

@@ -29,6 +29,7 @@ data_files =
     share/kolla/vagrant = vagrant/*
     share/kolla = tools/init-runonce
     share/kolla = tools/openrc-example
+    share/kolla = build.ini
 
 scripts =
     tools/kolla-ansible