Allow for setting debug and verbose config options

Right now, nova.conf hard codes verbose = true. Similarly there is no
way to turn on debug mode. This change simply adds two attributes for
both verbose and debug and makes use of them in the nova.conf template.

Change-Id: Ica613abb4e2d3719acaf1c9a4cb01fe92fd11774
Merge "Allow for setting debug and verbose config options"