chg: make `chg --cwd $anything -R $relativepath` behave better...
chg: make `chg --cwd $anything -R $relativepath` behave better
We're seeing this kind of issue:
```
$ (cd repo1; chg --cwd ../repo2 -R .)
chg: abort: too many redirections.
Please make sure $path/hg is not a wrapper which changes sensitive environment variables before executing hg. If you have to use a wrapper, wrap chg instead of hg.
[255]
```
chgserver is interpreting -R as relative to its cwd, instead of
relative to --cwd like regular hg does, which I think causes an
inconsistency leading to the above.
Differential Revision:
https://phab.mercurial-scm.org/D12579
