Many versions of Review Board currently have a bug where sending an unknown value in the tool= parameter to the repository list API would cause a crash. We'll be shipping a fix for that, but unfortunately there are a variety of released versions where the Git and Clearcase clients can trigger this crash on servers that do not have Power Pack installed. This change fixes the RBTools side to not include the Power Pack SCMTool names, which will avoid the problem for existing servers. For new servers, we'll be shipping a server-side fix that fixes the crash, adds the SCMTool IDs to the capabilities, and allows us to pass SCMTool IDs rather than names to the repository list API. If we see the IDs in the capability blob, we can assume that we can pass the IDs, including potentially unknown IDs. This also fixes a problem where we were sometimes accessing the repository list API twice with exactly the same parameters. Testing Done: - Ran unit tests. - Verified that the repository list API was accessed using SCMTool names that did not include potentially missing ones when running against an older server. - Verified that the repository list API was accessed with SCMTool IDs when running against a server with the new API fixes.