Precise developers & testers: please hold off on upgrading today

[Kate Stewart]

An issue has been noticed due to interaction between a recent libc
upgrade and the nvidia graphics driver.   If you have nvidia hardware,
please avoid upgrading until this has been resolved. Investigation is
ongoing.

Details will be found and tracked in: 
https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers/+bug/929384

Thanks,  Kate