rhg: refactor to pass argv down, instead of caling args_os()...
rhg: refactor to pass argv down, instead of caling args_os()
This refactoring makes it easy to patch some command-line preprocessing into rhg.
We use this to support using rhg as a shebang interpreter, for example.
Differential Revision:
https://phab.mercurial-scm.org/D12543