Added the changes for Delta filter that should have been

part of 656ec87882ee74b192c4ea4a233a235eca7b04d4.

src/liblzma/common/filter_decoder.c

@@ -133,7 +133,7 @@ static const lzma_filter_decoder decoders[] = {
 	{
 		.id = LZMA_FILTER_DELTA,
 		.init = &lzma_delta_decoder_init,
-		.memusage = NULL,
+		.memusage = &lzma_delta_coder_memusage,
 		.props_decode = &lzma_delta_props_decode,
 	},
 #endif

src/liblzma/common/filter_encoder.c

@@ -159,7 +159,7 @@ static const lzma_filter_encoder encoders[] = {
 	{
 		.id = LZMA_FILTER_DELTA,
 		.init = &lzma_delta_encoder_init,
-		.memusage = NULL,
+		.memusage = &lzma_delta_coder_memusage,
 		.chunk_size = NULL,
 		.props_size_get = NULL,
 		.props_size_fixed = 1,