sdcm/fill_db_data: fix delay for each insert to workaround list order issue
sdcm/fill_db_data: fix delay for each insert to workaround list order issue

This patch fixed a script bug in bda7beb9b5d87ca5233da066119f7b9af2226876,
the delay isn't successfully added.

This patch is tested with debug message, the delay is truely added.

Signed-off-by: Amos Kong <eb01d8f828a6c9a20be4534e72e049aaf41503df@scylladb.com>

scylladb/scylla-cluster-tests,scylladb/scylla-longevity-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-longevity-tests,scylladb/scylla-longevity-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests