rgw: fix empty storage class on display of multipart uploads

Some multipart uploads do not have a stored storage class, however the
code is written such that an empty storage class is treated as the
"STANDARD" storage class. So when encoding the storage class in JSON,
use the canonical storage.

Signed-off-by: J. Eric Ivancich <[email protected]>

Author: ivancich

src/cls/rgw/cls_rgw_types.cc

@@ -194,7 +194,9 @@ void rgw_bucket_dir_entry_meta::dump(Formatter *f) const
   utime_t ut(mtime);
   encode_json("mtime", ut, f);
   encode_json("etag", etag, f);
-  encode_json("storage_class", storage_class, f);
+  encode_json("storage_class",
+	      rgw_placement_rule::get_canonical_storage_class(storage_class),
+	      f);
   encode_json("owner", owner, f);
   encode_json("owner_display_name", owner_display_name, f);
   encode_json("content_type", content_type, f);