py3: use pycompat.byteskwargs() to covert keys of kwargs to bytes

py3: use pycompat.byteskwargs() to covert keys of kwargs to bytes

Differential Revision: https://phab.mercurial-scm.org/D5286

--- a/hgext/fastannotate/context.py	Mon Nov 19 20:30:07 2018 +0300
+++ b/hgext/fastannotate/context.py	Mon Nov 19 21:11:08 2018 +0300
@@ -156,6 +156,7 @@
     }
 
     def __init__(self, **opts):
+        opts = pycompat.byteskwargs(opts)
         for k, v in self.defaults.iteritems():
             setattr(self, k, opts.get(k, v))