OnlineReindexer: log the success/failure numbers on exit

When the OnlineReindexer fails to reindex all changes it will not
activate the new index schema version. However, it may happen that only
there were only a few failures and that activating the new index schema
makes sense. Help the admins make the decision whether to activate the
new index schema version by logging the success/failure numbers in the
error_log.

Change-Id: I522e236ab1e9b60d5c3c7c215d8308972db45f70
1 file changed