archimport: handle pika escaping

archimport: handle pika escaping

Arch uses pika escaping in some places (but not all!). Specifically, commits of
the type 'patch' use pika escaping in the log entries, which we parse to know
what to add/delete and what to commit.

This patch checks for hints of pika escaping and asks tla to unescape for us.

Originally implemented by Penny Leach <penny@catalyst.net.nz>

Signed-off-by: Martin Langhoff <martin@catalyst.net.nz>
Signed-off-by: Junio C Hamano <junkio@cox.net>