Comment 2 for bug 1495948

Duplicate '-y' switch already fixed on Sep 9, 2015: https://github.com/openstack/fuel-main/commit/18f2c14a928bf3e92ccd4d868953361bed61614b

Also, if you have problems with mirror.fuel-infra.org it is always possible to switch to another mirror using the USE_MIRROR environment variable or provide your own mirror using MIRROR_UBUNTU variable.
Please read:
1. https://docs.fuel-infra.org/fuel-dev/buildsystem.html#other-options
2. https://github.com/openstack/fuel-main/blob/master/config.mk#L135-L187