609255 - fix coverity Defect Type: Memory - illegal accesses issues

https://bugzilla.redhat.com/show_bug.cgi?id=609255

12237 UNINIT Triaged Unassigned Bug Minor Fix Required
vlv_trim_candidates_byvalue() ds/ldap/servers/slapd/back-ldbm/vlv.c

Commit:
There is almost no chance to pass uninitialized typedown_value to
ber_bvecfree unless vlv_request_control value is NULL.  Anyway, we
init typedown_value to NULL.

ldap/servers/slapd/back-ldbm/vlv.c

@@ -1489,7 +1489,7 @@ vlv_trim_candidates_byvalue(backend *be, const IDList *candidates, const sort_sp
     PRUint32 current= 0;
     ID id = NOID;
     int found= 0;
-    struct berval **typedown_value;
+    struct berval **typedown_value = NULL;
 
     /* For non-matchrule indexing */
     value_compare_fn_type compare_fn= NULL;