Fix delete in db_ttl.cc

Summary: should delete the proper variable

Test Plan: make all check

Reviewers: haobo, dhruba

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D12921

utilities/ttl/db_ttl.cc

@@ -56,7 +56,7 @@ Status UtilityDB::OpenTtlDB(
   Status st;
   *dbptr = new DBWithTTL(ttl, options, dbname, st, read_only);
   if (!st.ok()) {
-    delete dbptr;
+    delete *dbptr;
   }
   return st;
 }