sha1_name: convert struct disambiguate_state to object_id

sha1_name: convert struct disambiguate_state to object_id

Convert struct disambiguate_state to use struct object_id by changing
the structure definition and applying the following semantic patch:

@@
struct disambiguate_state E1;
@@
- E1.bin_pfx
+ E1.bin_pfx.hash

@@
struct disambiguate_state *E1;
@@
- E1->bin_pfx
+ E1->bin_pfx.hash

@@
struct disambiguate_state E1;
@@
- E1.candidate
+ E1.candidate.hash

@@
struct disambiguate_state *E1;
@@
- E1->candidate
+ E1->candidate.hash

This conversion is needed so we can convert disambiguate_hint_fn later.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>