When someone is using the `TREES` setting for RBTools, it's common that they'll be using repository paths as the keys to that. In this case, a command like `rbt patch --print` would fail because it was trying to avoid initializing the scmtool, and then we never got the correct server URL. This makes it so if `TREES` is present in the configuration (and now also actually populated with data, since the default value will be {}), and we otherwise did not need the scmtool, we'll still attempt to initialize it. If we get it, then great, we can use it for TREES. If we don't, we ignore that and proceed as previous. Testing Done: - Ran unit tests. - Verified that when TREES was defined, we now were initializing the scmtool when running `rbt patch --print`.