object-file: fix memory leak in `force_object_loose()`

object-file: fix memory leak in `force_object_loose()`

We return an error when converting the given object to the compatibility
hash algorithm fails. This early return causes a memory leak though,
because we don't free the content buffer that we've already read before
via `odb_read_object_info_extended()`.

Plug the memory leak by creating a common exit path where the buffer
gets free'd.

Signed-off-by: Patrick Steinhardt <redacted>
Signed-off-by: Junio C Hamano <redacted>