Fix deploy guide build (missing kolla project reference)

Change-Id: I9e3650e83c72081ef2679fe01842bb9be6a4eb7c
Signed-off-by: Radosław Piliszek <radoslaw.piliszek@gmail.com>

deploy-guide/source/conf.py

@@ -299,5 +299,6 @@ pdf_documents = [
 # -- Options for openstackdocstheme -------------------------------------------
 
 openstack_projects = [
+    'kolla',
     'kolla-ansible',
 ]