Add a clean

We can add clean.json where needed.

Change-Id: I6006189e3a8a4d5cf836c3bed58cf11647ec6d6d
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>

clean.json

@@ -0,0 +1,5 @@
+{
+	"k8cpu": {
+		"Projects": ["/sys/src/9/k10/clean.json"]
+	}
+}