When we want to purge all deleted rows
we use "glance-manage db purge" or
"glance-manage purge_images_table"
then we never know how many deleted rows are still in a table.
So we need to launch the command many times until
the command reports that 0 rows were deleted in every table.
It's inconvenient.
The patch introduced new valid value for "max_rows".
If "max_rows" equals -1 all deleted rows are purged.
Closes-Bug: 1702445
Change-Id: Ia9811d93b1c0b67a1b29a9e8ee3e0fc098c57d4a
360dc45680