Ignore empty header line.

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

@@ -180,7 +180,9 @@ feature -- Header: adding
             		if line [line.count] = '%R' then
 						line.remove_tail (1)
             		end
-					add_header (line)
+					if not line.is_empty then
+						add_header (line)
+					end
             	end
 			end
 		end