In Brazilian Portuguese zero is singular

PluralizationRules was correct, but https://github.com/symfony/symfony/commit/324ad4ccfd631313d1e040cd2683c27007e75cf2 broke it.

Online references (in brazilian portuguese):

http://lgcooper.wordpress.com/2008/10/08/zero-e-plural-ou-singular/

http://g1.globo.com/platb/portugues/2007/04/
http://g1.globo.com/platb/portugues/2010/01/

http://duvidas.dicio.com.br/zero-grau-ou-zero-graus/

http://docs.translatehouse.org/projects/localization-guide/en/latest/l10n/pluralforms.html