Commit 119cd06 started setting the primary bool for the first
user-specified video even if user omitted the 'primary' attribute.
However this was done before the addition of the implicit device.
This broke startup of transient qemu domains with no <video>:
https://bugzilla.redhat.com/show_bug.cgi?id=1325757
Move this default to virDomainDefPostParseInternal,
after the addition of the implicit video device, to catch the implicit
video as well.
Tool such as libguestfs need the datacenter path to get access to disk
images. The ESX driver knows the correct datacenter path, but this
information cannot be accessed using libvirt API yet. Also, it cannot
be deduced from the connection URI in a robust way.
Expose the datacenter path in the domain XML as <vmware:datacenterpath>
node similar to the way the <qemu:commandline> node works. The new node
is ignored while parsing the domain XML. In contrast to <qemu:commandline>
it is output only.
