misc *.c: use designated initializers for struct assignments

Change a few miscellaneous non-designated initializer assignments to
use designated initializers.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

attr.c

@@ -80,7 +80,7 @@ static int attr_hash_entry_cmp(const void *unused_cmp_data,
  * Access to this dictionary must be surrounded with a mutex.
  */
 static struct attr_hashmap g_attr_hashmap = {
-	HASHMAP_INIT(attr_hash_entry_cmp, NULL)
+	.map = HASHMAP_INIT(attr_hash_entry_cmp, NULL),
 };
 
 /*

notes-merge.c

@@ -113,6 +113,7 @@ static struct notes_merge_pair *find_notes_merge_pair_pos(
 }
 
 static struct object_id uninitialized = {
+	.hash =
 	"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" \
 	"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
 };

object-file.c

@@ -274,10 +274,11 @@ static struct cached_object {
 static int cached_object_nr, cached_object_alloc;
 
 static struct cached_object empty_tree = {
-	{ EMPTY_TREE_SHA1_BIN_LITERAL },
-	OBJ_TREE,
-	"",
-	0
+	.oid = {
+		.hash = EMPTY_TREE_SHA1_BIN_LITERAL,
+	},
+	.type = OBJ_TREE,
+	.buf = "",
 };
 
 static struct cached_object *find_cached_object(const struct object_id *oid)