Implement support for passing custom command line arguments
to bhyve using the 'bhyve:commandline' element:
<bhyve:commandline>
<bhyve:arg value='-newarg'/>
</bhyve:commandline>
* Define virDomainXMLNamespace for the bhyve driver, which
at this point supports only the 'commandline' element
described above,
* Update command generation code to inject these command line
arguments between driver-generated arguments and the vmname
positional argument.
Signed-off-by: Roman Bogorodskiy <bogorodskiy@gmail.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>