tests/krate/publish: Fix new_krate_tarball_with_hard_links()

The test was receiving "too large when decompressed" because of a broken header checksum, which was mistakenly converted into this error message, because we assume that every `entries()` error is coming from our `LimitErrorReader`.  This commit moves the checksum calculation to the right place, which causes the test to now test the correct condition in our `verify_tarball()` function.

Author: Turbo87

src/tests/krate/publish.rs

@@ -876,9 +876,9 @@ fn new_krate_tarball_with_hard_links() {
         let mut header = tar::Header::new_gnu();
         assert_ok!(header.set_path("foo-1.1.0/bar"));
         header.set_size(0);
-        header.set_cksum();
         header.set_entry_type(tar::EntryType::hard_link());
         assert_ok!(header.set_link_name("foo-1.1.0/another"));
+        header.set_cksum();
         assert_ok!(ar.append(&header, &[][..]));
         assert_ok!(ar.finish());
     }
@@ -890,9 +890,7 @@ fn new_krate_tarball_with_hard_links() {
         .bad_with_status(StatusCode::OK);
 
     assert!(
-        json.errors[0]
-            .detail
-            .contains("too large when decompressed"),
+        json.errors[0].detail.contains("invalid tarball uploaded"),
         "{:?}",
         json.errors
     );