Remove deprecated category/keyword helpers on blog posts, which existed for Django 1.3
Remove deprecated category/keyword helpers on blog posts, which existed for Django 1.3

Cicero-Zhao/mezzanine,wbtuomela/mezzanine,sjuxax/mezzanine,viaregio/mezzanine,readevalprint/mezzanine,stephenmcd/mezzanine,vladir/mezzanine,molokov/mezzanine,christianwgd/mezzanine,gradel/mezzanine,douglaskastle/mezzanine,stephenmcd/mezzanine,gradel/mezzanine,eino-makitalo/mezzanine,Cicero-Zhao/mezzanine,sjuxax/mezzanine,sjdines/mezzanine,frankier/mezzanine,vladir/mezzanine,jerivas/mezzanine,sjdines/mezzanine,jerivas/mezzanine,eino-makitalo/mezzanine,dsanders11/mezzanine,molokov/mezzanine,ryneeverett/mezzanine,douglaskastle/mezzanine,viaregio/mezzanine,frankier/mezzanine,dsanders11/mezzanine,eino-makitalo/mezzanine,ryneeverett/mezzanine,christianwgd/mezzanine,frankier/mezzanine,sjuxax/mezzanine,vladir/mezzanine,spookylukey/mezzanine,jerivas/mezzanine,spookylukey/mezzanine,stephenmcd/mezzanine,viaregio/mezzanine,readevalprint/mezzanine,spookylukey/mezzanine,ryneeverett/mezzanine,dsanders11/mezzanine,gradel/mezzanine,molokov/mezzanine,sjdines/mezzanine,wbtuomela/mezzanine,douglaskastle/mezzanine,wbtuomela/mezzanine,christianwgd/mezzanine,readevalprint/mezzanine