make concise
make concise

Make logical operations more simple and concise due to use 'host' instead of separate values 'host_os' and 'host_cpu'.
dmitryrck/wkhtmltopdf_binary_gem,zakird/wkhtmltopdf_binary_gem,dmitryrck/wkhtmltopdf_binary_gem,dmitryrck/wkhtmltopdf_binary_gem