Update obfs4proxy to 0.0.5, remove the old go.net code.
New tag for socks5 and to change the upstream dependency.
The new tag gets:
- SOCKS5 support, for obfs4proxy's PTs, separate from legacy/trac#12535 (moved).
- Changed from
golang.org/x/netfor a dependency.
The gitian descriptor already handles pulling down the required code from the new location thanks to legacy/trac#15265 (moved), so all that's left is to remove the mentions of the old code and stop fetching the tarball from my people.tp.o directory, and updating the tag.