cros_mark_as_stable: remove old kernel hack
cros_mark_as_stable: remove old kernel hack

This is no longer needed due to recent cleanup of the ebuild:

http://git.chromium.org/gitweb/?p=chromiumos-overlay.git;a=commit;h=2c58ec2cabfbd2658cc48b2c0cf74e6b5759b483

BUG=11124
TEST=See below.

$ export CROS_WORKON_LOCALNAME="kernel" CROS_WORKON_PROJECT="kernel" eval $(grep -E ^"^CROS_WORKON" kernel-9999.ebuild) && echo $CROS_WORKON_PROJECT $CROS_WORKON_LOCALNAME/$CROS_WORKON_SUBDIR
kernel "../third_party/kernel/files"/

Change-Id: Ib9b0d89b41753b490a9f1e73095ad106beefffa6

Review URL: http://codereview.chromium.org/6328005

vmware/coreos-scripts,trnubo/scripts,marineam/coreos-scripts,gtank/scripts,mischief/scripts,sigma/coreos-scripts,crawford/scripts,andrejro/coreos--scripts,BugRoger/scripts,gtank/scripts,endocode/scripts,vmware/coreos-scripts,sigma/coreos-scripts,fivethreeo/scripts,bcwaldon/coreos-scripts,trnubo/scripts,zhang0137/scripts,glevand/coreos--scripts,nicescale/scripts,zhang0137/scripts,mischief/scripts,coreos/scripts,nicescale/scripts,vmware/coreos-scripts,mjg59/scripts,gtank/scripts,sigma/coreos-scripts,fivethreeo/scripts,nicescale/scripts,glevand/coreos--scripts,zhang0137/scripts,bcwaldon/coreos-scripts,andrejro/coreos--scripts,crawford/scripts,marineam/coreos-scripts,smilart/scripts,BugRoger/scripts,mjg59/scripts,smilart/scripts,mischief/scripts,bcwaldon/coreos-scripts,crawford/scripts,coreos/scripts,endocode/scripts,mjg59/scripts,trnubo/scripts,endocode/scripts,andrejro/coreos--scripts,marineam/coreos-scripts,fivethreeo/scripts,BugRoger/scripts,smilart/scripts