Merge changes to validate.py to test.py

The following changes were only applied to validate.py, apply them to
test.py as well:
* print process message
* Handle removed files in tools/validate.py
* Fix output of --force
* Don't descent into target dirs
* Update DocBook validating schema to 5.1CR1
* Add a tiny bit more verbosity

Change-Id: Ia3ee355e0e87c5748d83ae670ca845ee30d9646d
Merge "Merge changes to validate.py to test.py"