Ensure demo user password is in overcloudrc-user

We're now generating a password for the demo user in the overcloud but
we're not including it in overcloudrc-user.

Change-Id: I2efb3b80df0aace90f2da501f839fe2f66141a9d
Allow create-nodes add to existing nodes

Interpret the $TOTAL arg as the number of new nodes to be created
and just add that number of new nodes if some already exist.

This allows us to create the seed baremetal node in one step and
then create the two undercloud baremetal nodes in another step.

Change-Id: Ie7b69584e348fbac24f09236c63ea42312ae5765
Add tripleo-incubator to pull-tools.

Adds the tripleo-incubator git repository to pull-tools.
Makes it easier to pull updates for all git repositories
used in devtest in one step.

Change-Id: I3e134f7f5c7fa03537012c37ee50601fbd6af75c
Use StrictHostKeyChecking set to no for init-keystone

Allows the user to not have to manually enter 'yes' during the run of
init-keystone.  Will allow init-keystone to be scripted as part of
devtest.sh, TOCI, etc.

Change-Id: I675ade1fa80365951e433a387eff22df18b871eb
Shellify the boot-seed-vm call in devtest.

Change-Id: I562716041f894d693429c6dee08ad8f6043e28fc
Shellify the undercloud image creation.

Change-Id: I69d840c83f0ec6487a0623f27bd488e0d305620f
Make DHCP driver explicit.

Once we have fully transitioned this can be made implicit again.

Change-Id: Ida2119c0320f0d02cd87d002a02a3ce7d4c755f3
Merge "Allow create-nodes add to existing nodes"
Merge "Use StrictHostKeyChecking set to no for init-keystone"
Set the overcloud to use qemu hypervisors.

Cause devtest describes emulated environments.

Change-Id: Id010c7da29ee9f4ea1946b8f7614624056775439
Merge "Add tripleo-incubator to pull-tools."
Merge "Ensure demo user password is in overcloudrc-user"