patch 8.0.1382: get "no write since last change" message if terminal is open

Problem:    Get "no write since last change" message if a terminal is open.
            (Fritz mehner)
Solution:   Don't consider a buffer changed if it's a terminal window.
diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index fc55815..cd8b0c3 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -1482,7 +1482,7 @@
 #endif
 		&& msg_silent == 0)
 	FOR_ALL_BUFFERS(buf)
-	    if (bufIsChanged(buf))
+	    if (bufIsChangedNotTerm(buf))
 	    {
 #ifdef FEAT_GUI_MSWIN
 		if (!winstart)