socketserver renaming reversal part 2: move rename module.

I'm doing this case-only rename in a two-step process via a different directory
to hopefully avoid problems with case-insensitive filesystems.

diff --git a/Lib/socketserver.py b/Lib/lib-old/SocketServer.py
similarity index 100%
rename from Lib/socketserver.py
rename to Lib/lib-old/SocketServer.py