[LU-16435] don't keep bad local copies of config llogs

• Type: Improvement
• Resolution: Not a Bug
• Priority: Minor
• Assignee: Mikhail Pershin
• Reporter: Mikhail Pershin

Description

The mgc_llog_local_copy() does two-step backup of llogs:

1. local copy to a temporary file
2. remote llog to local copy

though failure in either one are ignored and doesn't prevent mount the reason of failure can be corrupted local copy which will cause mount failure later while being processed.

To prevent that the mgs_llog_local_copy() should delete local copy if first backup failed due to any reason