Add sys-kernel/exynos-kernel to the blacklist
Add sys-kernel/exynos-kernel to the blacklist

At the moment, we have a public daisy overlay but the kernel
source can't be made public just quite yet.  ...for now we'll
prevent marking as stable so we don't mess up the paladin
builder.

See this CL for details on the failure that happened:
https://gerrit.chromium.org/gerrit/16518

BUG=None
TEST=None

Change-Id: I4bb8fb7155ecaf5ccb11dcc19487040e55b0bf80
Reviewed-on: https://gerrit.chromium.org/gerrit/16737
Reviewed-by: Katie Roberts-Hoffman <18b264b2ffd2bdd8a10fa2695b949fed75badc6b@chromium.org>
Commit-Ready: Doug Anderson <49983c4a76b998672954ed5edf4a62db4a336502@chromium.org>
Tested-by: Doug Anderson <49983c4a76b998672954ed5edf4a62db4a336502@chromium.org>

coreos/chromite,bpsinc-native/src_third_party_chromite,coreos/chromite,zhang0137/chromite,bpsinc-native/src_third_party_chromite,chadversary/chromiumos.chromite,chadversary/chromiumos.chromite,zhang0137/chromite,coreos/chromite,zhang0137/chromite,bpsinc-native/src_third_party_chromite