The tool= parameter for the repositories API was implemented using

SCMTool names, but we've had various issues in the past where names were

fluid for one reason or another. This change makes it so we can pass in

the SCMTool ID for this parameter as well.
Additionally, we had a bug where passing as unknown name to this

parameter would cause a crash in the API because the tool returned from

the registry lookup was None. This has been fixed to just skip adding

that to the list.

Ran unit tests.