This is a small improvement awaiting a definitive fix for
<https://issues.guix.gnu.org/45656>.
* guix/import/texlive.scm (sxml->package): Produce a warning when the SVN
checkout failed. Rather than crashing on the unexpected #f value, return a
partial package definition with the source field set to #f.
* guix/import/texlive.scm (fetch-sxml, sxml->package): Export.
* tests/texlive.scm <top level>: Call '%http-server-port'.
("fetch-sxml: returns SXML for valid XML"): Use 'with-http-server' and
set 'current-http-proxy' instead of using 'mock'.
("sxml->package"): Remove use of '@@'.
This fixes "guix import texlive translator".
* guix/import/texlive.scm (sxml->package): Add clause for when 'license'
is a list of licences, as is the case with the "translator" package.
