[Orgmode] Bug: export aborts if ':eval query/never' in source code blocks

[Paul Sexton]

#+BEGIN_SRC R :eval query
...
#+END_SRC

If the above is in an org file, the user runs an export (C-c C-e), and the user
types 'no' when asked whether to evaluate the code block, then the whole export
process is aborted (no further blocks are processed and no export output is
produced).

The same thing happens with ':eval never'.

Paul