MDEV-26: Global transaction ID.

Fix 3 small issues reported by Pavel Ivanov.

sql/mysqld.cc

@@ -840,8 +840,8 @@ static PSI_mutex_info all_server_mutexes[]=
   { &key_LOG_INFO_lock, "LOG_INFO::lock", 0},
   { &key_LOCK_thread_count, "LOCK_thread_count", PSI_FLAG_GLOBAL},
   { &key_PARTITION_LOCK_auto_inc, "HA_DATA_PARTITION::LOCK_auto_inc", 0},
-  { &key_LOCK_slave_state, "key_LOCK_slave_state", 0},
-  { &key_LOCK_binlog_state, "key_LOCK_binlog_state", 0}
+  { &key_LOCK_slave_state, "LOCK_slave_state", 0},
+  { &key_LOCK_binlog_state, "LOCK_binlog_state", 0}
 };
 
 PSI_rwlock_key key_rwlock_LOCK_grant, key_rwlock_LOCK_logger,

sql/rpl_gtid.cc

@@ -295,6 +295,7 @@ rpl_slave_state::record_gtid(THD *thd, const rpl_gtid *gtid, uint64 sub_id,
   list_element *elist= 0, *next;
   element *elem;
   ulonglong thd_saved_option= thd->variables.option_bits;
+  Query_tables_list lex_backup;
 
   mysql_reset_thd_for_next_command(thd, 0);
 
@@ -304,6 +305,7 @@ rpl_slave_state::record_gtid(THD *thd, const rpl_gtid *gtid, uint64 sub_id,
                     return 1;
                   } );
 
+  thd->lex->reset_n_backup_query_tables_list(&lex_backup);
   tlist.init_one_table(STRING_WITH_LEN("mysql"),
                        rpl_gtid_slave_state_table_name.str,
                        rpl_gtid_slave_state_table_name.length,
@@ -393,6 +395,7 @@ end:
     else
       thd->mdl_context.release_transactional_locks();
   }
+  thd->lex->restore_backup_query_tables_list(&lex_backup);
   thd->variables.option_bits= thd_saved_option;
   return err;
 }

sql/sys_vars.cc

@@ -3424,7 +3424,8 @@ bool update_multi_source_variable(sys_var *self_var, THD *thd,
   bool result= true;
   Master_info *mi;
 
-  mysql_mutex_unlock(&LOCK_global_system_variables);
+  if (type == OPT_GLOBAL)
+    mysql_mutex_unlock(&LOCK_global_system_variables);
   mysql_mutex_lock(&LOCK_active_mi);
   mi= master_info_index->
     get_master_info(&thd->variables.default_master_connection,
@@ -3438,7 +3439,8 @@ bool update_multi_source_variable(sys_var *self_var, THD *thd,
     mysql_mutex_unlock(&mi->rli.run_lock);
   }
   mysql_mutex_unlock(&LOCK_active_mi);
-  mysql_mutex_lock(&LOCK_global_system_variables);
+  if (type == OPT_GLOBAL)
+    mysql_mutex_lock(&LOCK_global_system_variables);
   return result;
 }