Set up bitbake to use local hackbox2 mirror

Set up a RO mirror /var/cache/yocto_cache to reduce the build time from 5 to 1 hour. The RO mirror /var/cache/yocto_cache will be populated every weekend.

Use the old OE hash signature generator. The new hash signature generator needs a hash server. The Yocto upstream hash server makes bitbake hang. Setting up a local hash server is recommended to improve build times.

Signed-off-by: Javier Tia javier.tia@linaro.org