Remove iolist_size(Data) == 0 case from send_chunk

This case is handled by start_delayed_response functions.

src/couch_httpd.erl

diff --git a/src/couch_httpd.erl b/src/couch_httpd.erl
index 7687453..15d43d0 100644
--- a/src/couch_httpd.erl
+++ b/src/couch_httpd.erl
@@ -584,10 +584,7 @@
 
 
 send_chunk(Resp, Data) ->
-    case iolist_size(Data) of
-        0 -> ok; % do nothing
-        _ -> Resp:write_chunk(Data)
-    end,
+    Resp:write_chunk(Data),
     {ok, Resp}.
 
 last_chunk(Resp) ->