Remove TRIPLEO_ROOT and pull-tools

tripleo-incubator hasn't been cloned at this point so we can't call
pull-tools, devtest_setup.sh will do this when the job runs. Removing
pull-tools means there is no longer a need for TRIPLEO_ROOT.

Change-Id: Id7b356c644894dbd6335423d81cb6f2d2261a2fb
Switch path to toci_gate_test.sh

/opt/stack/new/tripleo-ci will has been cloned by
devstack-gate/devstack-vm-gate-wrap.sh and is at the version we need.

Change-Id: If8f8ad7da86d3cb97e7f12695e3dafb6dd0698c4