Remove unused variables and label

libmysqld/lib_sql.cc:
  Remove unused variable and unused label
server-tools/instance-manager/guardian.cc:
  Remove unused variable
server-tools/instance-manager/mysql_connection.cc:
  Add cast to avoid warning
sql/ha_partition.cc:
  Remove unused variable(s) and an unused label

libmysqld/lib_sql.cc

@@ -274,7 +274,6 @@ static int emb_stmt_execute(MYSQL_STMT *stmt)
 {
   DBUG_ENTER("emb_stmt_execute");
   char header[5];
-  MYSQL_DATA *res;
   THD *thd;
 
   int4store(header, stmt->stmt_id);
@@ -1033,7 +1032,6 @@ void Protocol_simple::prepare_for_resend()
   data->embedded_info->prev_ptr= &cur->next;
   next_field=cur->data;
   next_mysql_field= data->embedded_info->fields_list;
-err:
   DBUG_VOID_RETURN;
 }
 

server-tools/instance-manager/guardian.cc

@@ -201,8 +201,6 @@ void Guardian_thread::run()
 
     while (node != NULL)
     {
-      struct timespec timeout;
-
       GUARD_NODE *current_node= (GUARD_NODE *) node->data;
       instance= ((GUARD_NODE *) node->data)->instance;
       process_instance(instance, current_node, &guarded_instances, node);

server-tools/instance-manager/mysql_connection.cc

@@ -136,7 +136,7 @@ int Mysql_connection_thread::init()
   /* Initialize random number generator */
   {
     ulong seed1= (ulong) &rand_st + rand();
-    ulong seed2= rand() + time(0);
+    ulong seed2= (ulong) rand() + time(0);
     randominit(&rand_st, seed1, seed2);
   }
   /* Fill scramble - server's random message used for handshake */

sql/ha_partition.cc

@@ -1135,7 +1135,6 @@ int ha_partition::handle_opt_partitions(THD *thd, HA_CHECK_OPT *check_opt,
     partition_element *part_elem= part_it++;
     if (all_parts || part_elem->part_state == PART_CHANGED)
     {
-      handler *file;
       if (m_is_sub_partitioned)
       {
         List_iterator<partition_element> sub_it(part_elem->subpartitions);
@@ -2311,7 +2310,7 @@ int ha_partition::open(const char *name, int mode, uint test_if_locked)
 err_handler:
   while (file-- != m_file)
     (*file)->close();
-err:
+
   DBUG_RETURN(error);
 }
 
@@ -2915,7 +2914,6 @@ int ha_partition::rnd_init(bool scan)
   int error;
   uint i= 0;
   uint32 part_id;
-  handler **file;
   DBUG_ENTER("ha_partition::rnd_init");
 
   include_partition_fields_in_used_fields();