appveyor: use ascii directory name
appveyor: use ascii directory name

It is a workaround that groonga/grndb can't be found by command_line
test case on worker image.

NOTE: directory name issue should be fixed.

groonga/groonga,komainu8/groonga,kenhys/groonga,groonga/groonga,kenhys/groonga,naoa/groonga,komainu8/groonga,groonga/groonga,kenhys/groonga,groonga/groonga,komainu8/groonga,naoa/groonga,groonga/groonga,naoa/groonga,naoa/groonga,komainu8/groonga,naoa/groonga,naoa/groonga,naoa/groonga,groonga/groonga,komainu8/groonga,kenhys/groonga,komainu8/groonga,kenhys/groonga,kenhys/groonga,kenhys/groonga,groonga/groonga,groonga/groonga,kenhys/groonga,naoa/groonga,komainu8/groonga,komainu8/groonga