BUG: plotting grouped_hist with a single row frame #10214
closes #10214 

Thanks! I think it can be in 0.16.2 (being released before 0.17.0), if you move release note description from "0.17.0.txt" to "0.16.2.txt" locates on the same directory. If you have any trouble, please feel free to ask.
 I did it https://github.com/scls19fr/pandas/tree/hist-ndim

see https://github.com/pydata/pandas/compare/master...scls19fr:hist-ndim

How should I submit my changes in same PR ? I wonder if committing in my branch also update this PR ?
 I should fix https://github.com/pydata/pandas/issues/10214
 pls see contribution guidelines [here](http://pandas.pydata.org/pandas-docs/stable/contributing.html)

to update, you simply push a new commit. don't open and close different PR's that is confusing.

if you squash/rebase, then `git push user-name branch-name -f`
 pls squash.  @TomAugspurger ok with you?
 Just gave a quick look. I think it's ok. 
 I'm quite busy. Could you squash ? Thanks
 merged via https://github.com/pydata/pandas/commit/a8b5798b31f04705bd421a2902c523f927eb6b7e

thanks!
