This patch replaces the error-prone manual locking with the use of the
'Synced_interface' for the motherboard and the VCPU dispatcher. It also
removes all globally visible locks. Locks are now explicitly passed to
subsystems when needed.
Vancouver is now able to use the Intel 82576 device model from NUL to
give VMs access to the network via the nic_bridge service. In order to
integrate the device model, it had to be renamed to i82576 due to XML
limitations. This is done by a patch applied via the 'make prepare'
mechanism.
Although current network card models in Vancouver panic if they can't
get a MAC address, the OP_GET_MAC hostop now fails gracefully in the
case where no nic_drv or nic_bridge is available.
