patch 7.4.1051

Problem:    Segfault when unletting "count".
Solution:   Check for readonly and locked first. (Dominique Pelle)
            Add a test.

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1051,
 /**/
     1050,
 /**/