remotefilelog: fix logging in retry decorator

remotefilelog: fix logging in retry decorator

This still fails with an error about no exception being available to
re-raise, but so it goes.

Differential Revision: https://phab.mercurial-scm.org/D5600

--- a/hgext/remotefilelog/basestore.py	Wed Jan 16 10:56:15 2019 -0500
+++ b/hgext/remotefilelog/basestore.py	Wed Jan 16 10:57:38 2019 -0500
@@ -420,6 +420,7 @@
                 except KeyError:
                     pass
             # retries exhausted
-            retrylog('retries exhausted in %s, raising KeyError\n' % funcname)
+            retrylog('retries exhausted in %s, raising KeyError\n' %
+                     pycompat.sysbytes(funcname))
             raise
         return wrapped