patch 9.0.0970: Coverity warns for uninitialized variable

Problem:    Coverity warns for uninitialized variable.
Solution:   Initialize "ren_ret".
diff --git a/src/version.c b/src/version.c
index 78df0d8..7ac20cd 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    970,
+/**/
     969,
 /**/
     968,