add clean up for re-runs

Author: Vitaly Korolev

makefile

@@ -233,6 +233,7 @@ upgrade-test: prepare
 .PHONY: image-scan
 image-scan:
 
+	@rm -f helm_image.list dep-image-scan.txt
 	@echo "=====Scan dependent Docker images in charts/values.yaml" $(if $(saveOutput), | tee -a dep-image-scan.txt,)
 	@for depImage in $(shell grep -E "^\s*\bimage:\s+(.*)" charts/values.yaml | sed 's/image: //g' | sed 's/"//g'); do\
 		echo -n "$${depImage}," >> helm_image.list ; \