Add support for setting Neutron DHCP agent options.

This patch adds support for setting arbitrary Neutron DHCP agent options.
An example of using it would be to add this to your localrc:

    Q_DHCP_EXTRA_DEFAULT_OPTS=(enable_multihost=True)

Change-Id: I56d267eafa06c52c3867e3396483f5fde3ee5570
change quantum into neutron for neutron configuration values in nova.conf

Change quantum into neutron Since nova already
supports the new neutron items and values

Change-Id: I747eae613c0ec28596ea67da4e98fb3d7f6d93bc
Fixes: Bug #1216455
VMware: update cinder support for VMware configuration settings

The review https://review.openstack.org/#/c/41600 was update to
have a 'vmware' prefix for all of the VMware cinder settings. These
were previously in a 'vmware' section and now they are in the
'DEFAULT' section.

Change-Id: I8eadfb0f64914d3b0667760aff651415df48f627
add TEMPEST_LARGE_OPS_NUMBER to option

The tempest scenario.large_ops test tries to catch any performance issues
when running large numbers of operations at once, in this case launching
instances.

Set to 0 by default, to maintain the current default, but add this as an
option so this can be set via devstacks localrc.

Part of regression test for bug 1199433

Change-Id: I459717b849f9b6d180a7956c0ff470cefe7c1ff6
Merge "change quantum into neutron for neutron configuration values in nova.conf"
Merge "VMware: update cinder support for VMware configuration settings"
Merge "Add support for setting Neutron DHCP agent options."
Merge "add TEMPEST_LARGE_OPS_NUMBER to option"