testdata_cfht and obs_cfht (or obs_decam, testdata_decam) won't get pulled for the default Jenkins build of lsst_distrib or lsst_sims, which are the standard products that are built by the hourly build.
Eventually, there's a larger question of how to include testdata_* in adding to CI, but adding this to lsstsw/etc/repos.yaml doesn't immediately change anything. However, it does make it easier to use the standard eups distrib or lsstsw builds of these additional packages.
I would bet that most changes to lsstsw and particularly for etc/repos.yaml will be associated with some ticket that was mostly about working on some other product.
I give the (thumbsup) to merge the additional lines in the repo.yaml file to master.