fix regression: uncork when HTTPS is used in conjunction with empty response body

ChangeLog

@@ -1,3 +1,7 @@
+Sat 26 Oct 2019 06:53:05 PM CEST
+    Fix regression where MHD would fail to return an empty response
+    when used with HTTPS. -CG/TR
+
 Fri 25 Oct 2019 02:31:59 PM CEST
     Introduce MHD_RF_INSANITY_HEADER_CONTENT_LENGTH. -CG