coreos-init: remove default coreos-setup-environment

The coreos-setup-environment script can now only be provided by OEMs,
the default script that used to run when the OEM didn't provide one was
not smart enough to wait for networking to be configured before writing
out /etc/environment *but* we cannot simply add such a wait because that
would make it impossible for users to use cloud config in configdrive or
similar to configure static networking.

Longer term coreos-cloudinit will replace at least some of the current
OEM coreos-setup-environment scripts and perhaps eventually integrate
with networkd to cover the default case reasonably well. Sorting this
out is still ongoing.

(This ebuild bump was supposed to land a week ago but we missed it.)
Merge pull request #717 from marineam/init

coreos-init: remove default coreos-setup-environment
Revert "oem-ec2-compat: Check for metadata service and config drive"

The functionality for this in cloudinit 0.8.x is broken.

This reverts commit 91cc8446212c6b35c80cbdbbc204a9fe3cd1f756.
coreos-cloudinit: roll back to 0.7.7, the 0.8.x series still needs work.