cmake: build for debug by default but let that var overriden.
cmake: build for debug by default but let that var overriden.

ignatenkobrain/hawkey,megaumi/hawkey,rpm-software-management/hawkey,MichaelMraka/hawkey,mluscon/hawkey,yavor-atanasov/hawkey,mizdebsk/hawkey,Conan-Kudo/hawkey,Conan-Kudo/hawkey,rholy/hawkey,Conan-Kudo/hawkey,MichaelMraka/hawkey,cgwalters/hawkey,jsilhan/hawkey,jsilhan/hawkey,yavor-atanasov/hawkey,megaumi/hawkey,mizdebsk/hawkey,megaumi/hawkey,Conan-Kudo/hawkey,jsilhan/hawkey,mizdebsk/hawkey,ignatenkobrain/hawkey,ignatenkobrain/hawkey,cgwalters/hawkey,rholy/hawkey,yavor-atanasov/hawkey,rholy/hawkey,mluscon/hawkey,megaumi/hawkey,jsilhan/hawkey,cgwalters/hawkey,rpm-software-management/hawkey,MichaelMraka/hawkey,ignatenkobrain/hawkey,rpm-software-management/hawkey,mluscon/hawkey,rpm-software-management/hawkey,yavor-atanasov/hawkey,mluscon/hawkey,cgwalters/hawkey,mizdebsk/hawkey,rholy/hawkey,MichaelMraka/hawkey