patch 9.1.1302: Coverity warns about using uninitialized value

Problem:  Coverity warns about using uninitialized value
          (Coverity, Tony Mechelynck, after v9.1.1301)
Solution: initialize callback pointer to NULL

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/version.c b/src/version.c
index 2758382..90ddf0b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1302,
+/**/
     1301,
 /**/
     1300,