Do not call the tap's initialization as soon as the -z option is read,

Do not call the tap's initialization as soon as the -z option is read,
postpone it after the preferences callback has being called.

That way mate's fields, which are registered by the preferences callback
can be used as part of the tap's filter.

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@13469 f5534014-38df-0310-8fa8-9805f1628bb7