Issue Summary

Build log line at the beginning of build is invisible for build result labeller feature.

This is reproducible on Data Center: yes

Steps to Reproduce

1. Configure job to add label with pattern 
   started building on agent ([^,]*)
2. Add \1 as label parameter
3. Run build at remote agent

Expected Results

Build has label with agent name after finishing

Actual Results

Build doesn't have required label as build log with agent info is not processed by build-labeller plugin

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available