Synchronize Module: Improved sudo override behaviour.

Here is a pull request based on the discussion in issue #5251 'synchronize module: override sudo settings'

This is based on a suggestion by @jctanner to only override the runner's sudo setting if the transport is set to local.

SInce the module often overrides the transport and sudo, I thought best to store the original setting for easier debugging and easier to understand code.

I also use a variable 'transport_overridden' to allow checking later in the module.