patch 8.0.1205: it is possible to unload a changed buffer

Problem:    Using "1q" it is possible to unload a changed buffer. (Rick Howe)
Solution:   Check the right window for changes.
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 905cdd4..ea6df86 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -7245,8 +7245,8 @@
      */
     if (check_more(FALSE, eap->forceit) == OK && only_one_window())
 	exiting = TRUE;
-    if ((!buf_hide(curbuf)
-		&& check_changed(curbuf, (p_awa ? CCGD_AW : 0)
+    if ((!buf_hide(wp->w_buffer)
+		&& check_changed(wp->w_buffer, (p_awa ? CCGD_AW : 0)
 				       | (eap->forceit ? CCGD_FORCEIT : 0)
 				       | CCGD_EXCMD))
 	    || check_more(TRUE, eap->forceit) == FAIL