Rename sha1_array to oid_array

Since this structure handles an array of object IDs, rename it to struct
oid_array.  Also rename the accessor functions and the initialization
constant.

This commit was produced mechanically by providing non-Documentation
files to the following Perl one-liners:

    perl -pi -E 's/struct sha1_array/struct oid_array/g'
    perl -pi -E 's/\bsha1_array_/oid_array_/g'
    perl -pi -E 's/SHA1_ARRAY_INIT/OID_ARRAY_INIT/g'

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin/diff.c b/builtin/diff.c
index a5b34eb..d184aaf 100644
--- a/builtin/diff.c
+++ b/builtin/diff.c
@@ -184,7 +184,7 @@ static int builtin_diff_combined(struct rev_info *revs,
 				 struct object_array_entry *ent,
 				 int ents)
 {
-	struct sha1_array parents = SHA1_ARRAY_INIT;
+	struct oid_array parents = OID_ARRAY_INIT;
 	int i;
 
 	if (argc > 1)
@@ -193,10 +193,10 @@ static int builtin_diff_combined(struct rev_info *revs,
 	if (!revs->dense_combined_merges && !revs->combine_merges)
 		revs->dense_combined_merges = revs->combine_merges = 1;
 	for (i = 1; i < ents; i++)
-		sha1_array_append(&parents, &ent[i].item->oid);
+		oid_array_append(&parents, &ent[i].item->oid);
 	diff_tree_combined(ent[0].item->oid.hash, &parents,
 			   revs->dense_combined_merges, revs);
-	sha1_array_clear(&parents);
+	oid_array_clear(&parents);
 	return 0;
 }