[17.0] auditlog : Add log_export_data field to ensure consitency

[svanerp]

A few days ago, on branch 16.0, a field appeared in the auditlog.rule class: log_eport_data.
Unfortunately, it is not present on branch 17.0 and I do not see any pending PRs.
On branch 18.0, the field is present again.
My guess is that the field first appeared in 18.0 and then a backport was made to 16.0.
The purpose of this PR is to ensure the consistency of the module by adding the missing field in 17.0.

[StefanRijnhart]

Only adding the one field is not useful. The missing feature shouldn't hurt anybody, not even those migrating from 16 to 18. If you want, you can port the whole feature, which indeed was only implemented for 16 and 18: #2768, #3338.