* bhyve_command.c (bhyveBuildNetArgStr, virBhyveProcessBuildBhyveCmd):
  add dryRun mode which doesn't create any devices when enabled
* bhyve_command.c (virBhyveProcessBuildBhyveCmd,
  virBhyveProcessBuildDestroyCmd, virBhyveProcessBuildLoadCmd): accept
  virDomainDefPtr instead of virDomainObjPtr.