MINOR: mux-h1: Set CS_FL_EOS when read0 is detected and no data are pending

In h1_process(), instead of setting CS_FL_REOS in this case, it is more accurate
to set CS_FL_EOS.
diff --git a/src/mux_h1.c b/src/mux_h1.c
index 4b0dab3..58e0879 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -1699,7 +1699,7 @@
 		if (h1c->flags & H1C_F_CS_ERROR || conn->flags & CO_FL_ERROR)
 			flags |= CS_FL_ERROR;
 		if (conn_xprt_read0_pending(conn))
-			flags |= CS_FL_REOS;
+			flags |= CS_FL_EOS;
 		h1s->cs->flags |= flags;
 		h1s->cs->data_cb->wake(h1s->cs);
 	}