On the verify-at-commit branch, remove the in-trunk now-obsolete implementation,
and simplify code.

* subversion/libsvn_fs/fs-loader.c
  (svn_fs_commit_txn): Don't verify, compute 'fs' more simply.

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/verify-at-commit@1462402 13f79535-47bb-0310-9956-ffa450edef68