Upgrade hook v44 fixes
Upgrade hook v44 fixes

- do test for chromium/src before fixing the checkout.
- don't switch manifests for minilayout users.

BUG=chromium-os:32963
TEST=locally

Change-Id: I1d0cbfc9f4f03d85b34810cdb98d99a7a21d8adf
Reviewed-on: https://gerrit.chromium.org/gerrit/28842
Reviewed-by: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>
Tested-by: Ryan Cui <5ce1592d53754a87a44fc2eb7b63d5f77cf50fdb@chromium.org>
Commit-Ready: Ryan Cui <5ce1592d53754a87a44fc2eb7b63d5f77cf50fdb@chromium.org>

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