clone: simplifying dest repo creation since creating a repo raises an exception if the repo already exists, there's no need to try to create one. add some test for repo creation when the destination exists

#!/bin/sh

hg init
mkfifo p

hg serve --stdio < p &
P=$!
(echo lock; echo addchangegroup; sleep 5) > p &
Q=$!
sleep 3
kill -HUP $P
wait
ls .hg