Remove unnecessary brackets in regex (closes #5715)

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4668 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activesupport/lib/active_support/inflections.rb

@@ -36,7 +36,7 @@
   inflect.singular(/(o)es$/i, '\1')
   inflect.singular(/(shoe)s$/i, '\1')
   inflect.singular(/(cris|ax|test)es$/i, '\1is')
-  inflect.singular(/([octop|vir])i$/i, '\1us')
+  inflect.singular(/(octop|vir)i$/i, '\1us')
   inflect.singular(/(alias|status)es$/i, '\1')
   inflect.singular(/^(ox)en/i, '\1')
   inflect.singular(/(vert|ind)ices$/i, '\1ex')