someone only want to save failed logs

[wgameking]

Hi,At first thanks for developing this plugin,
Can you provider an option to download failed logs,because success logs mean worthless to me and occupy lot space in my slave.

[per-bohlin]

I've added the possibility to use it as a build-step.
If you are still in need of only saving failed logs, you can setup a conditional post-build step that only runs if the build is in failed.
I've added a pull-request:
#2

If you don't want to wait for the pull request to get merged, you can get the code at:
https://github.com/devconsoft/jenkins-log-console-log