updated ChangeLog for perf_metrics and trace_logger removal
updated ChangeLog for perf_metrics and trace_logger removal

F1000Research/khmer,ged-lab/khmer,F1000Research/khmer,souravsingh/khmer,souravsingh/khmer,souravsingh/khmer,ged-lab/khmer,F1000Research/khmer,ged-lab/khmer