Check for end-of-buffer

Enabling judge-indent in a buffer where the last line starts with an
indentation immediately followed by EOB with no newline currently fails:

  $ echo -n '\n\t' >foo
  $ emacs -batch -Q -l judge-indent.el ./foo -f judge-indent-mode
  Loading vc-git...
  Wrong type argument: characterp, nil

This patch makes sure that `char-equal` is not called with an argument
of `nil`.
Merge pull request #1 from yibe/eob-check

Check for end-of-buffer