updated for version 7.4.031

Problem:    ":diffoff!" resets options even when 'diff' is not set. (Charles
            Cooper)
Solution:   Only resets related options in a window where 'diff' is set.

src/version.c

@@ -738,6 +738,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    31,
 /**/
     30,
 /**/