Post review fix of Bug#17431 INSERT IGNORE INTO returns failed: 1296: err 4350...

Post review fix of Bug#17431 INSERT IGNORE INTO returns failed: 1296: err 4350 'Transaction already aborted', shared locking is sufficient

sql/ha_ndbcluster.cc

@@ -1560,8 +1560,7 @@ int ha_ndbcluster::peek_indexed_rows(const byte *record)
   int res;
   DBUG_ENTER("peek_indexed_rows");
 
-  NdbOperation::LockMode lm=
-    (NdbOperation::LockMode)get_ndb_lock_type(m_lock.type);
+  NdbOperation::LockMode lm= NdbOperation::LM_Read;
   first= NULL;
   if (table->s->primary_key != MAX_KEY)
   {