- this is needed for packaging, so that all possible tarballs can be
  available in the complete source package

Do not define tarball names in configure. Move the variables into
download.lst, which is going to be included in config_host.mk.
We already have conditions for getting tarballs in Makefile.fetch.

Change-Id: I160aff6426a253814eea07d2467e4942478f653a