Don't keep running SetEngine in migration_test (#12860)
Don't keep running SetEngine in migration_test (#12860)

There's no need to keep repeatedly running SetEngine in migration_test,
as NewEngine calls it anyway.

Signed-off-by: Andrew Thornton <6a547fdd28db89120bdd70d4af1f9ba672ccd43a@cantab.net>
go-gitea/gitea,sapk-fork/gitea,sapk-fork/gitea,sapk-fork/gitea,cez81/gitea,vdbt/gitea,vdbt/gitea,sapk-fork/gitea,cez81/gitea,go-gitea/gitea,go-gitea/gitea,cez81/gitea