image: Do not set journal_model=WAL for the Hurd.

image: Do not set journal_model=WAL for the Hurd.

This fixes <https://bugs.gnu.org/42151>.

* gnu/system/images/hurd.scm (hurd-initialize-root-partition): Use #:wal-mode #f
in call to ...
* gnu/build/image.scm (initialize-root-partition): ... this, add #:wal-mode?
parameter, pass it to ...
(register-closure): ... this, add #:wal-mode? parameter, pass it to ...
* guix/store/database.scm (with-database): ... this, add #:wal-mode?
parameter, pass it to ...
(call-with-database): ... this, add #:wal-mode? parameter; when
set to #f, do not set journal_model=WAL.