Use rbind for ChromeOS source directory
Use rbind for ChromeOS source directory

I use a mount at src/build/images to stop image builds from repeatedly
filling up my SSD. The chroot needs to respect this.

TEST=cros_sdk
BUG=none

Change-Id: I5c7a26c3b4f263bd683d3a897e6edccb83187bda
Reviewed-on: https://gerrit.chromium.org/gerrit/47178
Reviewed-by: Mike Frysinger <8f3f75c74bd5184edcfa6534cab3c13a00a2f794@chromium.org>
Commit-Queue: Michael Spang <e1fb1a05abba8fb04acbcbe6d766da7764320db0@chromium.org>
Tested-by: Michael Spang <e1fb1a05abba8fb04acbcbe6d766da7764320db0@chromium.org>

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