BUG/MINOR: httpclient: process the response when received before the end of the request

A server could reply a response with a shut before the end of the htx
transfer, in this case the httpclient would leave before computing the
received response.

This patch fixes the issue by calling the "process_data" label instead of
the "more" label which don't do the si_shut.

Must be bacported in 2.5.

src/http_client.c

@@ -728,7 +728,7 @@ static void httpclient_applet_io_handler(struct appctx *appctx)
 						appctx->st0 = HTTPCLIENT_S_RES_STLINE;
 					}
 
-					goto more; /* we need to leave the IO handler once we wrote the request */
+					goto process_data; /* we need to leave the IO handler once we wrote the request */
 				}
 			break;