del some unneeded op

models/custom_migrations.go

@@ -15,13 +15,9 @@ type CustomMigrationStatic struct {
 	Migrate     func(*xorm.Engine, *xorm.Engine) error
 }
 
-var customMigrations = []CustomMigration{
-	{"Custom v1 Topic struct change to support chinese", syncTopicStruct},
-}
+var customMigrations []CustomMigration
 
-var customMigrationsStatic = []CustomMigrationStatic{
-	{"update issue_fixed_rate to 1 if num_issues is 0 ", updateIssueFixedRate},
-}
+var customMigrationsStatic []CustomMigrationStatic
 
 func MigrateCustom(x *xorm.Engine) {