Increase git clone depth from 1 to 50 on AppVeyor.
Increase git clone depth from 1 to 50 on AppVeyor.

When a pending build task on CI build server gets started, in theory
there is a chance that the commit to be tested is not included within
the last N commits from the HEAD.

This CL increases the clone depth on AppVeyor from 1 to 50, to match
the default parameter that has been used in Travis-CI.

kbc-developers/Mozc,kbc-developers/Mozc,fcitx/mozc,fcitx/mozc,kbc-developers/Mozc,kbc-developers/Mozc,fcitx/mozc,google/mozc,google/mozc,google/mozc,kbc-developers/Mozc,fcitx/mozc,google/mozc,fcitx/mozc,kbc-developers/Mozc,google/mozc,kbc-developers/Mozc