py3: use pycompat.byteskwargs() to convert opts keys to bytes

Differential Revision: https://phab.mercurial-scm.org/D2319

hgext/mq.py

@@ -2267,7 +2267,7 b' def delete(ui, repo, *patches, **opts):'
     To stop managing a patch and move it into permanent history,
     use the :hg:`qfinish` command."""
     q = repo.mq
-    q.delete(repo, patches, opts)
+    q.delete(repo, patches, pycompat.byteskwargs(opts))
     q.savedirty()
     return 0