Convert from using FLAGS directly in SF driver.

In order for the Filter scheduler to be used to it's
full advantage Cinder drivers need to move away from
using FLAGS directly and switch to appending their
specific options to self.configuration.

This patch converts the driver and updates tests.

Fixes bug: 1131553

Change-Id: Id1a7c583894ac368bdcc61facc6f72300db320c7
Merge "Convert from using FLAGS directly in SF driver."