py3: make scmutil.rcpath() return bytes 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.

py3: use pycompat.ossep at certain places Certain instances of os.sep has been converted to pycompat.ossep where it was sure to use bytes only. There are more such instances which needs some more attention and will get surely.

py3: have pycompat.ospathsep and pycompat.ossep We needed bytes version of os.sep and os.pathsep in py3 as they return unicodes.