facecolor/edgecolor are passed arguments to savefig if they
differ from rcParam['figure.facecolor']
From nilearn
CLN: Fix typo in comment
Merge pull request #3964 from bwignall/boostdoctypo

CLN: Fix typo in comment
Fixed a bug in RFECV when step != 1
Merge pull request #3824 from nmayorov/rfecv_bugfix

[MRG+1] FIX: Bug in RFECV when step is not 1
Merge pull request #3953 from Titan-C/savefigarg

 Use correct savefig arguments in gen_rst.py