BUG: Series.align(join='left') and join='right' are inverted

[gdementen]

join='left' does a right join and 'right' does a left join

See the notebook for details
https://nbviewer.jupyter.org/gist/gdementen/fa4d388993ee981b5698

[gdementen]

btw, this is with pandas 0.16.2

[gdementen]

probably related to (possibly a dupe of, I am not sure) #10147.
The strange thing, is that for DataFrames, align seems to work correctly.

[sinhrks]

Thanks. Looks to be caused by the following lines.

• https://github.com/pydata/pandas/blob/master/pandas/core/index.py#L2152

When Series with MultiIndex is on left side, how=left and right must be flipped also. PR is appreciated!