Remove transactions' need to count references to cachefiles (they already have references to brts)
Errors in rolling back certain functions were ignored (r = blah; return something_else);
They are now reported, so diskfull had to be updated to expect ENOSPC under certain circumstances.

git-svn-id: file:///svn/toku/tokudb@11371 c7de825b-a66e-492c-adef-691d508d4ae1