It seems like after a build the /dl dir seems to now contain a .hash
file for each source file due to inproper cleanup so fix it by removing
those intermediate files before leaving the download action.
Fixes: 4e19cbc553 ("download: handle possibly invalid local tarballs")
Reported-by: Hannu Nyman <hannu.nyman@iki.fi>
Signed-off-by: Petr Štetiar <ynezz@true.cz>