journal: Don't try to write garbage if journal entry is corrupted

journal: Don't try to write garbage if journal entry is corrupted

If journal_file_data_payload() returns -EBADMSG or -EADDRNOTAVAIL,
we skip the entry and go to the next entry, but we never modify
the number of items that we pass to journal_file_append_entry_internal()
if that happens, which means we could try to append garbage to the
journal file.

Let's keep track of the number of fields we've appended to avoid this
problem.