Esta linha vai te dar o que você quer:
zstyle ':completion:*:*:svn-add:*:*files' ignored-patterns '*?.aux' '*?.bbl' \
'*?.blg' '*?.out' '*?.log' '*?.toc' '*?.snm' '*?.nav' '*?.pdf' '*?.bak' '*\~'
De link :
The command or a special -context-, just at it appears following the #compdef tag or the compdef function. Completion functions for commands that have sub-commands usually modify this field to contain the name of the command followed by a minus sign and the sub-command. For example, the completion function for the cvs command sets this field to cvs-add when completing arguments to the add subcommand.