tests/test-push-hook-lock

Create local ui object per repository, so .hg/hgrc don't get mixed.
This is needed for hooks, but may be important for other settings, too.
Fixes issue113, also integrated push-hook-lock.sh as a test case for this.

#!/bin/sh
hg init 1
echo '[ui]' >> 1/.hg/hgrc
echo 'timeout = 10' >> 1/.hg/hgrc
echo foo > 1/foo
hg --cwd 1 ci -A -m foo
hg clone 1 2
hg clone 2 3
echo '[hooks]' >> 2/.hg/hgrc
echo 'changegroup.push = hg push -qf ../1' >> 2/.hg/hgrc
echo bar >> 3/foo
hg --cwd 3 ci -m bar
hg --cwd 3 push ../2