fix

Author: sousinha1997

pyperf/pyperf_run

@@ -81,7 +81,7 @@ generate_csv_file()
 
   $TOOLS_BIN/test_header_info --front_matter --results_file "${1}.csv" --host $to_configuration --sys_type $to_sys_type --tuned $to_tuned_setting --results_version $PYPERF_VERSION --test_name $test_name_run
 
-	echo "Test:Avg:Unit" > "${1}.csv"
+	echo "Test:Avg:Unit" >> "${1}.csv"
 	while IFS= read -r line
 	do
 		if [[ $test_name == "" ]]; then