coreos-firmware: remove coreos-sources from runtime dependencies

Fixes commit 3f028060 which mistakenly added coreos-sources as both
build and run-time dependencies. This was missed initially because there
are exclude rules that remove /usr/src from production images but it
does needlessly slow down the build and pulls in extraneous kernel build
dependencies like perl.

Prune old releases, no need for them.
Merge pull request #1010 from marineam/firmware

coreos-firmware: remove coreos-sources from runtime dependencies
coreos-kernel: bump stable to 3.17.7, testing to 3.18.1
Merge pull request #1013 from marineam/kernel

coreos-kernel: bump stable to 3.17.7, testing to 3.18.1
coreos-base/oem-azure: always restart waagent
Merge pull request #1014 from crawford/waagent

coreos-base/oem-azure: always restart waagent
add open-vmdk 1.0 (utility to create vmware ova files)
add open-vmdk to sdk-depends
Merge pull request #1015 from vmware/open-vmdk

add open-vmdk 1.0 (utility to create vmware ova files)
app-emulation/docker: add --insecure-registry flag

This is a temporary workaround to allow people to transistion into 1.3+
smoothly. This sets --insecure-registry=0.0.0.0/0 to maintain backward
compatibility.
Merge pull request #1016 from crawford/docker

app-emulation/docker: add --insecure-registry flag