Update bootstraps

Add `atbuild bootstrap` task to update all bootstraps
2 jobs for master in 7 minutes and 42 seconds
Status Job ID Name Coverage
  Build
failed #4465
autoscale-linux
linux

00:05:52

passed #4466
openswift
osx

00:01:50

 
Name Stage Failure
failed
linux Build There is an unknown failure, please try again
Ign http://httpredir.debian.org jessie InRelease
Get:2 http://httpredir.debian.org jessie-updates InRelease [142 kB]
Get:3 http://httpredir.debian.org jessie Release.gpg [2373 B]
Get:4 http://security.debian.org jessie/updates/main amd64 Packages [365 kB]
Get:5 http://httpredir.debian.org jessie Release [148 kB]
Get:6 http://httpredir.debian.org jessie-updates/main amd64 Packages [17.6 kB]
Get:7 http://httpredir.debian.org jessie/main amd64 Packages [9032 kB]

ERROR: Build failed: exit code 137