Update cbuildbot to use git.chromium.org instead of src.chromium.org.
Update cbuildbot to use git.chromium.org instead of src.chromium.org.

src.chromium.org is no longer supported for git operations.

BUG=chromium-os:7830
TEST=none

Change-Id: Ia7cd9ff76625441f16d20d2f9a8e0f752dca0586

Review URL: http://codereview.chromium.org/3782010

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