Fixed HTTP_HEADER.put_raw_header (..) by ignoring any empty line of the argument value.

(note: "%R" is considered as empty line here.)

library/network/protocol/http/src/http_header.e

@@ -228,10 +228,12 @@ feature -- Header: merging
             		if line [line.count] = '%R' then
 						line.remove_tail (1)
             		end
+					if not line.is_empty then
 						put_header (line)
 					end
             	end
 			end
+		end
 
 	put_array (a_headers: ARRAY [TUPLE [key: READABLE_STRING_8; value: READABLE_STRING_8]])
 			-- Append array of key,value headers