tests: remove networkRegister() call from qemuxml2argvtest

Further cleanup from

  commit 0c63c117
  Author: Daniel P. Berrangé <berrange@redhat.com>
  Date:   Fri Feb 9 15:08:53 2018 +0000

    conf: reimplement virDomainNetResolveActualType in terms of public API
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

tests/qemuxml2argvtest.c

@@ -25,7 +25,6 @@
 # include "cpu/cpu_map.h"
 # include "virstring.h"
 # include "storage/storage_driver.h"
-# include "network/bridge_driver.h"
 # include "virmock.h"
 
 # define __QEMU_CAPSPRIV_H_ALLOW__
@@ -586,9 +585,6 @@ mymain(void)
     if (qemuTestDriverInit(&driver) < 0)
         return EXIT_FAILURE;
 
-    if (networkRegister() < 0)
-        return EXIT_FAILURE;
-
     driver.privileged = true;
 
     VIR_FREE(driver.config->defaultTLSx509certdir);