Docker images: use -py with vim73, and -py3 with vim-master (#966)
Docker images: use -py with vim73, and -py3 with vim-master (#966)

Ref: https://github.com/neomake/neomake/pull/942#issuecomment-275246779
bonds/neomake,euclio/neomake,codeinabox/neomake,bonds/neomake,nerdrew/neomake,euclio/neomake,neomake/neomake,neomake/neomake,nerdrew/neomake