Bug 22283: Linux 7.0a4 broken after update

Improve our torrc fixup code to remove all ControlPort and SocksPort
lines that contain a Unix domain socket, and execute the fixup one
more time. This corrects a problem where the torrc of alpha channel
users who transitioned from Unix domain sockets to TCP was left
with ControlPort and SocksPort lines that contained bad paths (the
parent directory for the Unix domain socket did not exist).