[O] :mkdirp without path specifier

[Michael Weylandt]

If it intended that setting :mkdirp yes should break tangling with 
'directory-free' file names?

I.e., should
#############
#+TITLE: test
#+BEGIN_SRC python :mkdirp yes :tangle test.py
print 1+2
#+END_SRC
###############

tangle without error? 

It currently doesn't because (file-name-directory "test.py"), which is nil, 
gets passed to make-directory, which throws an error. 

The manual is ambiguous, stating only that the arg to :tangle is interpreted as 
a path. A strict reading says this shouldn't work, regardless of :mkdirp, since 
we're not giving a path, but I think the "understood ./" of :mkdirp no is 
reasonable. 

I'm not in a position to do so now, but can send a one-line patch to fix 
tonight if wanted. 

Michael