FIXME: Add --force-yes to apt-get dist-upgrade.

FIXME: Add --force-yes to apt-get dist-upgrade.

arm64 udev in Ubuntu Trusty is broken, so we had to provide our own
patched udev package in armband MOS repos.

Due to dpkg version comparison algorithm, our MOS version of udev
is considered a downgrade, which requires --force-yes for
apt-get dist-upgrade to work and pick up this version, otherwise
bootstrap/target image build would fail with apt-get error code 100.

This change can be dropped later, if other packages do not manifest
the same behavior.

Change-Id: I00f6a55290f2d09fd6aacfa948c84e39da27923d