svn-download: Do not expand keywords.

Subversion keyword expansion is potentially non-reproducible as some of
them expand time strings relative to the local time zone:

  https://issues.guix.gnu.org/43442#18

In practice this is not a problem in Guix since Subversion checkouts
happen in an isolated environment using the "default timezone" (UTC).

However, Software Heritage disables keyword expansion for this very
reason.  By following suit, we make sure content can be retrieved from
there.

* guix/build/svn.scm (svn-fecth): Pass "--ignore-keywords" to
Subversion.
* guix/build-system/texlive.scm (%texlive-date): New variable.
* gnu/packages/java.scm (java-geronimo-xbean-reflect)
(java-geronimo-genesis-2.1): Update the source hash.
* gnu/packages/machine-learning.scm (ghmm): Likewise.
* gnu/packages/video.scm (libsmpeg, libsmpeg-with-sdl1): Likewise.
* gnu/packages/tex.scm (texlive-bin): Update the hash of the
"texlive-scripts" input, and a add a new phase that imitates
Subversion keyword expansion for scripts that need it.
(texlive-latex-base): Update the hash of the "texlive-luatexconfig"
native input.
(texlive-hyphen-base, texlive-dvipdfmx, texlive-dvips, texlive-cm)
(texlive-tex-plain, texlive-kpathsea, texlive-latexconfig)
(texlive-tetex, texlive-pdftex, texlive-xetex): Update the source
hash.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>

gnu/packages/machine-learning.scm

@@ -239,7 +239,7 @@ classification.")
                 (file-name (string-append name "-" version "-checkout"))
                 (sha256
                  (base32
-                  "0qbq1rqp94l530f043qzp8aw5lj7dng9wq0miffd7spd1ff638wq"))))
+                  "07kdsngvr4n1qxpqzv1nlay7g41d6jzjppa8vzmrg220s8ing87z"))))
       (build-system gnu-build-system)
       (arguments
        `(#:imported-modules (,@%gnu-build-system-modules