Added dl alias to download discriminator

lib/sde-clean/download.in

@@ -15,7 +15,7 @@
 #Description: Removes old downloads from your old local download mirror. 
 #Description: Only downloads still specified in .desc files will not be 
 #Description: removed.
-#Alias: 
+#Alias: dl
 
 echo_abort 1 "Not yet implemented"