run merge program in repo root.
before, merge program was run in user current directory. Well defined
location is better for scripts. no more need to pass HG_ROOT to merge
program now.
#!/bin/sh
set -e
mkdir test
cd test
echo foo>foo
hg init
hg addremove
hg commit -m "1"
hg verify
hg clone . ../branch
cd ../branch
hg co
echo bar>>foo
hg commit -m "2"
cd ../test
hg pull ../branch
hg verify
hg co
cat foo
hg manifest