tests/test-gendoc-pt_BR.t

tests: setup dummyssh as the default ssh

To significantly reduce boilerplate in tests. One test is updated to
show that it works, I expect to do the rest in follow up commits.

Differential Revision: https://phab.mercurial-scm.org/D11244

#require docutils gettext

  $ $TESTDIR/check-gendoc pt_BR
  checking for parse errors