Issue 51059 - If dbhome directory is set online backup fails
Bug Description: If the dbhome directory is set, eg to /dev/shm/instance
then an online backup fails because it looks for the log.000000x file
in the wring diretcory.
This is hidden because the return code is overwritten before checking.
Fix Description: If dblayer_backup function fails - go to error processing
section.
https://pagure.io/389-ds-base/issue/51059
Reviewed by: mreynolds (Thanks!)