Bug in backup log file numbering

[christopherwharrop]

The following was reported by Gerard Ketefian:

Hi (Chris?),

Just wanted to report a minor bug in rocoto that I've noticed for a long
time now but haven't gotten around to reporting.

As you know, when a task is called more than one time, the previous log
file(s) from that task get renumbered as [task_name].log.0,
[task_name].log.1, etc, with the largest integer corresponding to the
oldest file.

I've noticed that when the number of times a task is called reaches 10 or
more (e.g. due to issuing of repeated "rocotoboot"s), there are no
even-numbered task log files. For example, if the task name is make_grid,
then I get the following files:

$ ls -alF
make_grid.log
make_grid.log.0
make_grid.log.1
make_grid.log.11
make_grid.log.13
make_grid.log.15
make_grid.log.17
make_grid.log.2
make_grid.log.3
make_grid.log.4
make_grid.log.5
make_grid.log.6
make_grid.log.7
make_grid.log.8
make_grid.log.9

The one without a number at the end (in bold) is the log from the latest
execution of the task, and the others are from previous executions. You
can see that 10, 12, 14, 16, etc are missing.

I don't know what happens when you get to the 20's. I'm on hera and using
rocoto/1.3.1.