keys of keyword arguments on Python 3 has to be string. We are dealing with
bytes in our codebase so the keys are also bytes. Done that using
pycompat.strkwargs().
Also after this patch, `hg version` now runs on Python 3.5. Hurray!
"In this case, result is a source variable of a list to be returned, it
shouldn't be unicode. Hence we can use bytes instead of basestring here." -Yuya
This patch make sure scmutil.rcpath() returns bytes independent of
which platform is used on Python 3. If we want to change type for windows we
can just conditionalize the return variable.
This test helps us to keep track on the commands which runs to Python 3.
The full traceback is hidden. Thanks to Augie and Martijn to wrap it up
in four lines.
