resolve_ref_unsafe(): handle the case of an SHA-1 within loop

resolve_ref_unsafe(): handle the case of an SHA-1 within loop

There is only one "break" statement within the loop, which jumps to
the code after the loop that handles the case of a file that holds a
SHA-1.  So move that code from below the loop into the if statement
where the break was previously located.  This makes the logic flow
more local.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>