beta-code-update: dont mail build console

The code update job build log is too large and rejected by mailman:

Your mail to 'QA' with the subject
    beta-code-update-eqiad - Build # 9364 - Fixed!
Is being held until the list moderator can review it for approval.
The reason it is being held:
    Message body is too big: 571712 bytes with a limit of 40 KB

Change-Id: Ic44f28cf80682f2e6bbc1f2f7075fb4b28dd533c