Fix many ERRORs and a few WARNINGs when building Sphinx doc

This only contains docstring changes, no code has been modified.

Change-Id: I13e06c922caa2300ea3f17cab51f923c11997a3c
Remove obsolete YubiHSM prototype

The final yubihsm.py module is already contained in the security package
and yhsm.py is just a leftover.

Change-Id: Iec89262d5962e72c59e54d9fb56865385427c637
Make logging.config in SQLAudit work with Sphinx

The SQLAudit module does some module-level logger instantiation that
causes problems when building the Sphinx doc. To fix this we only
configure the logger when the pylons config file is not None.

Change-Id: I6ec7fa075e7a4cf1a1314aaf20986ed8a3cffd6c