MDEV-38598 : Galera test failure on MW-86-wait8

Test failure is caused by regression introduced by commit
4de773e that changed error code when function does not exists.

Author: janlindstrom

mysql-test/suite/galera/t/MW-86-wait8.test

@@ -67,7 +67,7 @@ SHOW DATABASES;
 --error 0
 SHOW ENGINE InnoDB STATUS;
 
---error ER_LOCK_WAIT_TIMEOUT
+--error ER_SP_DOES_NOT_EXIST
 SHOW FUNCTION CODE f1;
 
 --error ER_LOCK_WAIT_TIMEOUT
@@ -82,7 +82,7 @@ SHOW INDEX FROM t1;
 --error ER_LOCK_WAIT_TIMEOUT
 SHOW OPEN TABLES;
 
---error ER_LOCK_WAIT_TIMEOUT
+--error ER_SP_DOES_NOT_EXIST
 SHOW PROCEDURE CODE p1;
 
 --error ER_LOCK_WAIT_TIMEOUT