Rip out "ant init-forrest-entities" and the specversion variables from the tutorial.xml

Back in SOLR-238 we introduced ahook where forrest had access to the specversion as of the last time anyone ran an ant task in solr.

the primary reason for this was because we wanted the "live site" version of the tutorial to reflect the trunk, while the tutorial included in releases would be release specific.

But this process has proved incredibly tedious and error prone and in the long run shouldn't be needed anyway since we should ultimately adopt the same model for Solr Lucene-Java has been using for a while: distinct sets/directories for the live site and version specific documents (this is something that would be easiest to switch to when adopting the new Apache CMS - see LUCENE-2748)

So for now i suggest we just rip it out completely. it's already caused several problems as we prep for the 3.1.0 release.