patch 9.1.0478: potential deref of NULL pointer in fuzzy_match_str_with_pos

Problem:  potential deref of NULL pointer in fuzzy_match_str_with_pos()
          on cleanup (after v9.1.0476)
Solution: Only free the pointer if it is non-NULL (glepnir)

closes: #14973

Signed-off-by: glepnir <glephunter@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/version.c b/src/version.c
index cc24945..4b695c0 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    478,
+/**/
     477,
 /**/
     476,