convert: use return value in parse_view() instead of manipulating state

changegroup: simplify logic around enabling changegroup 03 There was multiple spot that took care of adding '03' as supported changegroup version for different condition. We gather them all in one location for simplicity. The 'supportedincomingversions' function is now doing nothing, but I kept it around because it looks like a great hooking point for extension. (Note that we should probably just get changegroup3 out of experimental now, But that would be a patch with a much wider scope).

changegroup: pass 'repo' to allsupportedversions In the next changesets, we will introduce more logic directly related to the repository to decide what version have to be supported. So we now directly pass the repo object instead of just ui.

changegroup: simplify 'allsupportedversions' logic Discarding '03' to add it back is a bit strange. Instead we only discard it when needed.

py3: replace os.altsep with pycompat.altsep All the occurences of os.altsep are replaced with pycompat.altsep which returns bytes.

py3: have a bytes version of sys.platform sys.platform returns unicodes on Python 3. This patch adds up pycompat.sysplatform which returns bytes.

py3: have a bytes version of os.altsep os.altsep returns unicodes on Python 3. We need a bytes version hence added pycompat.altsep.

py3: make sure encoding.encoding is a bytes variable encoding.encoding returns unicodes when locale.getpreferredencoding() is used to get the preferred encoding. This patch fixes that.

chg: remove locks See the previous two patches for the reason. The advantage is a simplified code base and better throughput when starting multiple servers with multiple confighashes. The disadvantage is starting multiple servers in parallel with a single confighash will waste some CPU time, which is probably fine in common use-cases. This makes it easier to switch to relative paths to support long unix domain socket paths.

chg: start server at a unique address See the previous patch for motivation. Previously, the server is started at a globally shared address. This patch appends pid to the address so it becomes unique. Note: with Linux pid namespace, the address may be non-unique, but it does not affect correctness of chg - chg client will receive an redirection and that's it.