Fix corrupt modified enum values

localtests/enum-modified/create.sql

@@ -0,0 +1,25 @@
+drop table if exists gh_ost_test;
+create table gh_ost_test (
+  id int auto_increment,
+  i int not null,
+  result enum('Pass', 'Fail') not null,
+  primary key(id)
+) auto_increment=1 default charset=latin1;
+
+insert into gh_ost_test values (1, 7, 'Pass');
+insert into gh_ost_test values (2, 8, 'Fail');
+insert into gh_ost_test values (3, 19, 'Pass');
+
+drop event if exists gh_ost_test;
+delimiter ;;
+create event gh_ost_test
+  on schedule every 1 second
+  starts current_timestamp
+  ends current_timestamp + interval 60 second
+  on completion not preserve
+  enable
+  do
+begin
+  insert into gh_ost_test (i, result) values(12345, 0);
+  insert into gh_ost_test (i, result) values(12345, 1);
+end ;;

localtests/enum-modified/extra_args

@@ -0,0 +1 @@
+--alter="modify column result enum('Pass', 'MostExcellent') not null"