remove some verbosity from last-theory-change and fix for rules that haven't ever been enabled/disabled

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2267 303c5b2c-9740-0410-b014-fd8f9db7be32
verified guards of map-aig-vars-fast

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2268 303c5b2c-9740-0410-b014-fd8f9db7be32