Clean old harnesses up.

Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
diff --git a/Makefile b/Makefile
index ec7c675..8e59acd 100644
--- a/Makefile
+++ b/Makefile
@@ -12,16 +12,19 @@
 clean-artix7-db:
 	rm -f $(addprefix artix7/,$(DATABASE_FILES))
 	rm -f $(addprefix artix7/timings/,$(TIMINGS_FILES))
+	rm -rf artix7/harness/
 	rm -rf $(addprefix artix7/,$(PART_DIRECTORIES))
 
 clean-kintex7-db:
 	rm -f $(addprefix kintex7/,$(DATABASE_FILES))
 	rm -f $(addprefix kintex7/timings/,$(TIMINGS_FILES))
+	rm -rf kintex7/harness/
 	rm -rf $(addprefix kintex7/,$(PART_DIRECTORIES))
 
 clean-zynq7-db:
 	rm -f $(addprefix zynq7/,$(DATABASE_FILES))
 	rm -f $(addprefix zynq7/timings/,$(TIMINGS_FILES))
+	rm -rf zynq7/harness/
 	rm -rf $(addprefix zynq7/,$(PART_DIRECTORIES))
 
 clean-db: clean-artix7-db clean-kintex7-db clean-zynq7-db