DOC: clean-up whatsnew file for 0.21.1#18690

Merged

jorisvandenbossche merged 3 commits intopandas-dev:masterfrom

jorisvandenbossche:doc-whatsnew-0211

Dec 10, 2017

Commits on Dec 8, 2017

DOC: clean-up whatsnew file for 0.21.1
jorisvandenbossche
committed

Commits on Dec 9, 2017

fix version number
jorisvandenbossche
committed

Commits on Dec 10, 2017

Merge remote-tracking branch 'upstream/master' into doc-whatsnew-0211
jorisvandenbossche
committed