test-help: improve test coverage
Adds a test for using the help option with the version option.
Extends test coverage of commands.help_ by another 2 lines.
Basic install:
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
See http://mercurial.selenic.com/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.