i#1784: drpreinject self-unload not properly disabled on win8+
i#1784: drpreinject self-unload not properly disabled on win8+

Fixes a bool vs BOOL bug where the drpreinject self-unload disable check
from i#1522 was not properly working for win8+.

Fixes #1784

Review-URL: https://codereview.appspot.com/263500044

AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio