Clarify logging with concurrent backupsets

[MikeG]

When you have multiple backupsets running concurrently, the log lines are interleaved in the holland.log

It would be much easier to understand these logs each line had a prefix of the backupset name being run.

Log sample from trunk:

2014-01-29 02:45:40,030 [INFO] Backup completed in 4 minutes, 42.95 seconds

It would be nice to tack the backupset name in there, something like:

2014-01-29 02:45:40,030 [INFO] (prod1) Backup completed in 4 minutes, 42.95 seconds

[MikeG (mikegriffin)]

Also consider PPID or something similar, so dry-run of "prod1" backupset is unambiguous while non dry-run of "prod1" backupset is running.

[MikeG (mikegriffin)]

Tacking this quasi related feature request rather than a new bug..

Clarify dry run logging. Sample:

2014-06-03 07:47:34,374 [INFO] Executing: /usr/bin/mysqldump --defaults-file=/var/spool/holland/default/20140603_074701/my.cnf --flush-privileges --max-allowed-packet=128M --lock-tables mysql
2014-06-03 07:47:34,387 [INFO] Backup completed in 32.51 seconds
2014-06-03 07:47:34,388 [WARNING] Extremely low free space on /var/spool/holland/default/20140603_074701's filesystem (/).
2014-06-03 07:47:34,388 [WARNING] 68.82MB of 84.83GB [0.08%] remaining
2014-06-03 07:47:34,397 [INFO] --- Ending dry run ---

2014-06-03 07:47:34,374 [INFO] Would execute: /usr/bin/mysqldump --defaults-file=/var/spool/holland/default/20140603_074701/my.cnf --flush-privileges --max-allowed-packet=128M --lock-tables mysql
2014-06-03 07:47:34,387 [INFO] Backup dry run completed in 32.51 seconds