patch 8.0.0155: ubsan complains about NULL pointer

Problem:    When sorting zero elements a NULL pointer is passed to qsort(),
            which ubsan warns for.
Solution:   Don't call qsort() if there are no elements. (Dominique Pelle)

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    155,
 /**/
     154,
 /**/