[PATCH 4/4] tests: Don't use exceptions for flow control

[Finucane, Stephen]

> Using exceptions for flow control is bad. Be consistent and instead
> use proper functions to check for version support. This also allows
> the use of tools to automatically identify feature flags when
> removing support for Django versions in the future.
> 
> Signed-off-by: Stephen Finucane <stephen.finucane at intel.com>

Merged.