LIT Output: Fix regression in 3.41 caused by py3 porting that broke conversion of some files to LIT. Fixes #1837561 [Lit conversion error (Conversion options changed from default)](https://bugs.launchpad.net/calibre/+bug/1837561)

src/calibre/ebooks/lit/writer.py

@@ -721,6 +721,8 @@ class LitWriter(object):
             dchunks.append(dchunk.getvalue())
             dcounts.append(dcount)
             if ichunk:
+                if not isinstance(name, bytes):
+                    name = name.encode('utf-8')
                 ichunk.write(decint(len(name)))
                 ichunk.write(name)
                 ichunk.write(decint(cid))