Comment 1 for bug 1710027

Forgot to mention: listing the files produces this:

-rw-rw---- 1 mysql mysql 125 Aug 10 22:51 xtrabackup_checkpoints
-rw-rw---- 1 mysql mysql 500 Aug 10 22:15 xtrabackup_info
-rw-rw---- 1 mysql mysql 8.0M Aug 10 22:51 xtrabackup_logfile
-rw-rw---- 1 mysql mysql 0 -8002387070795393024 xtrabackup_slave_info

I don't know that I need this file (this server is in a replicated pair), and applying innobackup to the resulting files does appear to work, but I'd prefer it if it didn't throw errors!