MINOR: stream-int: always report received shutdowns

As mentioned in c192b0ab95 ("MEDIUM: connection: remove CO_FL_CONNECTED
and only rely on CO_FL_WAIT_*"), si_cs_recv() currently does not propagate
CS_FL_EOS to CF_READ_NULL if CO_FL_WAIT_L4L6 is set, while this situation
doesn't exist anymore. Let's get rid of this confusing test.
diff --git a/src/stream_interface.c b/src/stream_interface.c
index a71b2d6..16bd3f8 100644
--- a/src/stream_interface.c
+++ b/src/stream_interface.c
@@ -1499,14 +1499,11 @@
 		ret = 1;
 	}
 	else if (cs->flags & CS_FL_EOS) {
-		/* connection closed */
-		if (!(conn->flags & CO_FL_WAIT_L4L6)) {
-			/* we received a shutdown */
-			ic->flags |= CF_READ_NULL;
-			if (ic->flags & CF_AUTO_CLOSE)
-				channel_shutw_now(ic);
-			stream_int_read0(si);
-		}
+		/* we received a shutdown */
+		ic->flags |= CF_READ_NULL;
+		if (ic->flags & CF_AUTO_CLOSE)
+			channel_shutw_now(ic);
+		stream_int_read0(si);
 		ret = 1;
 	}
 	else if (!si_rx_blocked(si)) {