subrepo: drop unused pattern initialization in hgsubrepo revert
This passed an empty list to filerevert() if '--all' was specified, otherwise
the set of modified files. But then filerevert() immediately switched this and
reinitialized 'pats' to an empty list if '--all' was *not* specified.
.. 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