We need notiication, if staging or chromeos scripts breaks

[nuclearcat]

When something breaks in staging or chromeos script (docker permission issues, rate limits, obsolete patch) often it breaks staging and we are not aware about that, sometimes up to several days.
I think it will be nice to have trap function in this scripts that invoke mail client and send alert to sysadmins/developers/deploy maintainers.

[gctucker]

If developers were using the results more often then it would be obvious... But yes, propagating error exit codes from the staging and chromeos scripts would help too.