Revert "NEXUS-6294: Deleted file handles."

This reverts commit 26a5dbe10f10e73a453c862e763d895b597656aa.
NEXUS-6294: Redoing change

Basically, not doing much, as only making sure that
after purge the deleted file handles are released for sure
(purge would introduce most change to index segments).

Also, not punishing any writer only the "batch" one
that is used only in special circumstances, like
"repair index" on boot, when timeline index is
detected corrupt.

Everything else left intact.