appveyor: add msys to the path
appveyor: add msys to the path

shlomif/black-hole-solitaire,shlomif/black-hole-solitaire,shlomif/black-hole-solitaire,shlomif/black-hole-solitaire,shlomif/black-hole-solitaire,shlomif/black-hole-solitaire