chore(coreos): upgrade to 379.3.0

This also bumps Docker to 1.1.1.

Note that this also changes the device names for EC2
and DigitalOcean, as CoreOS changed these as of 379.0.0.
Merge pull request #1345 from deis/coreos-379.3.0

chore(coreos): upgrade to 379.3.0 and Docker 1.1.1