Building the genesis-base deb failed at dh_installdocs because LICENSE.html
could not be found: only the debian/ directory and the source RPM were copied
into the build root, while debian/docs references LICENSE.html. Copy
LICENSE.html into the build root alongside debian/. Also drop the dead
'svn update' call left over from the pre-git build.
Signed-off-by: Daniel Hilst <392820+dhilst@users.noreply.github.com>