BUG#20848 SHOW STATUS LIKE 'NDB%' should be data nodes not storage nodes

use correct termninology

sql/ha_ndbcluster.cc

@@ -146,7 +146,7 @@ static long ndb_cluster_node_id= 0;
 static const char * ndb_connected_host= 0;
 static long ndb_connected_port= 0;
 static long ndb_number_of_replicas= 0;
-static long ndb_number_of_storage_nodes= 0;
+static long ndb_number_of_data_nodes= 0;
 
 static int update_status_variables(Ndb_cluster_connection *c)
 {
@@ -154,7 +154,7 @@ static int update_status_variables(Ndb_cluster_connection *c)
   ndb_connected_port=          c->get_connected_port();
   ndb_connected_host=          c->get_connected_host();
   ndb_number_of_replicas=      0;
-  ndb_number_of_storage_nodes= c->no_db_nodes();
+  ndb_number_of_data_nodes= c->no_db_nodes();
   return 0;
 }
 
@@ -163,7 +163,7 @@ struct show_var_st ndb_status_variables[]= {
   {"config_from_host",         (char*) &ndb_connected_host,      SHOW_CHAR_PTR},
   {"config_from_port",         (char*) &ndb_connected_port,          SHOW_LONG},
 //  {"number_of_replicas",     (char*) &ndb_number_of_replicas,      SHOW_LONG},
-  {"number_of_storage_nodes",(char*) &ndb_number_of_storage_nodes, SHOW_LONG},
+  {"number_of_data_nodes",(char*) &ndb_number_of_data_nodes, SHOW_LONG},
   {NullS, NullS, SHOW_LONG}
 };