Cause cros_workon to die rather than clobber local_manifest
Cause cros_workon to die rather than clobber local_manifest

cros_workon would clobber local edits to local_manifest in many cases
This is a quick fix to prevent it. The proper solution is to actually parse
local_manifest as an XML doc and modify the DOM. Not play tricks with grep.

BUG=chromium-os:6272
TEST=Ran cros_workon against missing local_manifest, auto-generated local_manifest, local_manifest with indented tags. local_manifest with multi-line tags and local_manifest with <remote tags.

Review URL: http://codereview.chromium.org/3227006

Change-Id: I008c11a43ac21336575445273453373645f96398

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