object-name.c: rename from sha1-name.c

Generalize the last remnants of "sha" and "sha1" in this file and rename
it to reflect that we're not just able to handle SHA-1 these days.

We need to update one test to check for an updated error string.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/list-objects-filter.c b/list-objects-filter.c
index 0a3ef3c..4ec0041 100644
--- a/list-objects-filter.c
+++ b/list-objects-filter.c
@@ -21,7 +21,7 @@
  * in the traversal (until we mark it SEEN).  This is a way to
  * let us silently de-dup calls to show() in the caller.  This
  * is subtly different from the "revision.h:SHOWN" and the
- * "sha1-name.c:ONELINE_SEEN" bits.  And also different from
+ * "object-name.c:ONELINE_SEEN" bits.  And also different from
  * the non-de-dup usage in pack-bitmap.c
  */
 #define FILTER_SHOWN_BUT_REVISIT (1<<21)