patch 7.4.1156

Problem:    Coverity warns for NULL pointer and ignoring return value.
Solution:   Check for NULL pointer. When dict_add() returns FAIL free the item.

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1156,
 /**/
     1155,
 /**/