tdf#128111: "adsrc" doesn't exist from Postgresql 12

tdf#128111: "adsrc" doesn't exist from Postgresql 12

Before Postgresql 8.0, there was only "adsrc"
then it's been deprecated
"The adsrc field is historical, and is best not used, because it does not track outside changes
 that might affect the representation of the default value.
 Reverse-compiling the adbin field (with pg_get_expr for example) is a better way to display the default value
"
and finally it's been removed with version 12

See evolution with:
- https://www.postgresql.org/docs/8/catalog-pg-attrdef.html
- https://www.postgresql.org/docs/11/catalog-pg-attrdef.html
- https://www.postgresql.org/docs/12/catalog-pg-attrdef.html

Merge with https://cgit.freedesktop.org/libreoffice/core/commit/?id=1ec93ef100bb5f6ccef91f12e28ed09feb3eb38b

Change-Id: I57e9da423a23b5a96bbb64b0e026b160e9643ab9
Reviewed-on: https://gerrit.libreoffice.org/80722
(cherry picked from commit 0c46c81e04530e8f6ce4f34195d8f0443ed8bfc3)
Reviewed-on: https://gerrit.libreoffice.org/80736
Tested-by: Jenkins
Reviewed-by: Julien Nabet <serval2412@yahoo.fr>
Gbp-Pq: Name Postgresql-12-no-adsrc.diff