Remove references to SVN/getpack

The first commit raises an exception if a project is not found in the SoftDB, rather than falling back to SVN (getpack).

Seeing some other references to getpack, I thought it might be useful to remove these in a second commit. The getpack binary doesn't seem to be availabe in an LbEnv environment, so I'm assuming it's not used anywhere. We can drop the second (more 'invasive') commit if getpack is still used.