subrepo: correctly handle update -C with modified subrepos (issue2022)
(based on a patch by Saint Germain)
#!/bin/shhg init aecho a > a/ahg --cwd a ci -A -m ahg clone a becho b > b/bhg --cwd b ci -A -m bchmod 100 a/.hg/storehg --cwd b push ../achmod 700 a/.hg/store