hg-ssh: exit with 255 instead of -1 on error
Unix sh would cast -1 to 255 anyway, but on windows -1 become 0. Better be
explicit with the 255 everywhere.
.. Common link and substitution definitions.
.. |hg(1)| replace:: **hg**\ (1)
.. _hg(1): hg.1.html
.. |hgrc(5)| replace:: **hgrc**\ (5)
.. _hgrc(5): hgrc.5.html
.. |hgignore(5)| replace:: **hgignore**\ (5)
.. _hgignore(5): hgignore.5.html