DPDK: Setup CPU affinity for QEMU in nova.conf.
DPDK: Setup CPU affinity for QEMU in nova.conf.

QEMU needs to be pinned to different cores than vRouter. This
change adds new fab task: setup_qemu_coremask. The task takes
vRouter core mask from testbed, computes core mask containing
cores other than vRouter's and calls openstack-config to append
vcpu_pin_set to /etc/nova/nova.conf.

Change-Id: Id1248a32b1bb3a6f3e3115ca41485838ff38d2c9
Closes-bug: #1511332

Juniper/contrail-fabric-utils,Juniper/contrail-fabric-utils