py3: use encoding.environ in ui.py Using source transformer we add b'' everywhere. So there are no chances that those bytes string will work with os.environ on Py3 as that returns a dict of unicodes. We are relying on the errors, even though no error is raised even in future, these pieces of codes will tend to do wrong things. if statements can result in wrong boolean and certain errors can be raised while using this piece of code. Let's not wait for them to happen, fix what is wrong. If this patch goes in, I will try to do it for all the cases. Leaving it as it is buggy.

py3: make scmposix.userrcpath() return bytes We are making sure that we deal with bytes as much we can. This is a part of fixing functions so that they return bytes if they have to. Used encoding.environ to return bytes. After this patch, scmposix.userrcpath() returns bytes and scmutil.osrcpath() will also return bytes if the platform is posix. Functions is scmposix returns bytes on Python 3 now.

adjustlinkrev: remove unnecessary parameters Since adjustlinkrev has "self", and is a method of a filectx object, it does not need path, filelog, filenode. They can be fetched from the "self" easily.

repair: make strip() return backup file path narrowhg wants to strip some commits and then re-apply them after applying another bundle. Having repair.strip() return the bundle path will be helpful for it.