Bug 35819: Add simple delay

Bug 35819: Add simple delay

Here I add 500 ms. In my testing with the 1s sleep from the test
plan, I might see one or two 'not found' lines. Obviously things
depend on the time needed before the txn commits. But it will
reduce a flood of these messages.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 0feb10df7f9473c8ccd14bea947c0957a839e059)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>