allow deleting excluded files with rsync

This option can't be added to both init and action, because the rsync
exclude mechanism is used to select the files to send, so would delete
all non-changed files. It's only relevant during init anyway, as after
that no excluded files will be made on the destination.

default-rsync.lua

@@ -62,6 +62,7 @@ rsync.checkgauge = {
 		copy_dirlinks     =  true,
 		copy_links        =  true,
 		cvs_exclude       =  true,
+		delete_excluded   =  true,
 		dry_run           =  true,
 		executability     =  true,
 		existing          =  true,
@@ -316,7 +317,7 @@ rsync.init = function
 
 	local filters = inlet.hasFilters( ) and inlet.getFilters( )
 
-	local delete   = nil
+	local delete   = {}
 
 	local target   = config.target
 
@@ -336,6 +337,11 @@ rsync.init = function
 		delete = { '--delete', '--ignore-errors' }
 	end
 
+	if config.rsync.delete_excluded == true
+	then
+		table.insert( delete, '--delete-excluded' )
+	end
+
 	if not filters and #excludes == 0
 	then
 		-- starts rsync without any filters or excludes