[FIXED JENKINS-22839] Allow clearing log recorders.
[FIXED JENKINS-22840] Make ring buffer size configurable
Merge branch 'JENKINS-22840' of github.com:daniel-beck/jenkins
[JENKINS-22840] Noting merge of #1220.
Merge branch 'JENKINS-22839' of github.com:daniel-beck/jenkins
[JENKINS-22839] Noting merge of #1219.