path UPDTAE deref func support in leafref (#2030)

diff --git a/src/hash_table.c b/src/hash_table.c
index 0523d8e..246fb34 100644
--- a/src/hash_table.c
+++ b/src/hash_table.c
@@ -537,7 +537,7 @@
     int32_t i;
     ly_bool first_matched = 0;
     LY_ERR r, ret = LY_SUCCESS;
-    lyht_value_equal_cb old_val_equal;
+    lyht_value_equal_cb old_val_equal = NULL;
 
     LY_CHECK_ERR_RET(lyht_find_first(ht, hash, &rec), LOGARG(NULL, hash), LY_ENOTFOUND); /* hash not found */