tests/ivshmem-test: Supply missing initializer in get_device()

If the device isn't found, the assertion uses dev without
initialization.  Fix that.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <1448384789-14830-4-git-send-email-armbru@redhat.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>

tests/ivshmem-test.c

@@ -40,6 +40,7 @@ static QPCIDevice *get_device(void)
     QPCIBus *pcibus;
 
     pcibus = qpci_init_pc();
+    dev = NULL;
     qpci_device_foreach(pcibus, 0x1af4, 0x1110, save_fn, &dev);
     g_assert(dev != NULL);