tests/qtest/migration: Rename fd_proto test

Next patch adds another fd test. Rename the existing one closer to
what's used on other tests, with the 'precopy' prefix.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240220224138.24759-3-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
1 file changed