tests/qtest/migration: Standardize hook names

Standardize the hook names:

- change the names to .start|end_hook to match
  test_migrate_start|end()

- use the migrate_hook_start_ and migrate_hook_end_ prefixes

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
1 file changed