[O] bug#34323: reproducibility: absolute file names in ox-odt.elc

[Glenn Morris]

Package: emacs,org-mode
Version: 26.1.91
Severity: minor

The compiled file ox-odt.elc contains strings that refer to the
absolute location of the build directory, through
org-odt-schema-dir-list and org-odt-styles-dir-list.
For example, in the Emacs 26.1.91 pretest tarfile, it contains
"/home/nico/work/emacs-26/etc/schema/" and
"/home/nico/work/emacs-26/etc/styles/".
This means the generated elc file is non-reproducible (ie, the contents
change depending on the build directory).

(Like https://debbugs.gnu.org/34321, issued spotted in
https://tests.reproducible-builds.org/debian/rb-pkg/unstable/amd64/diffoscope-results/emacs.html
)