scp2: fix windows build

913bf64b0bf1330a5055c26770faedf2ad7fc3c5 had some issues with redland
stuff that is built as Library on windows, and the libxslt package is
actually called "xslt" for unknown reasons; unfortunately the buildbot
did not actually try to create an installation set so it was not
detected.

Change-Id: I0437f09228f62b21036a6c26e3d17029d1aab79e