osdict: Move default_netmodel logic to Guest

Make the entry point just return a list of libosinfo device names,
and have Guest choose the preference. This is more future proof

virtinst/guest.py

@@ -1078,22 +1078,26 @@ class Guest(XMLBuilder):
                 disk.cli_generated_target = False
                 used_targets.append(disk.generate_target(used_targets))
 
-    def _set_net_defaults(self):
-        net_model = None
+    def _default_netmodel(self):
         if not self.os.is_hvm():
-            net_model = None
-        elif self._supports_virtio(self._os_object.supports_virtionet()):
-            net_model = "virtio"
-        else:
-            net_model = self._os_object.default_netmodel()
+            return None
+        if self._supports_virtio(self._os_object.supports_virtionet()):
+            return "virtio"
+        if self.os.is_q35():
+            return "e1000e"
 
-        if not net_model and self.os.is_q35():
-            net_model = "e1000e"
+        prefs = ["e1000", "rtl8139", "ne2k_pci", "pcnet"]
+        supported_models = self._os_object.supported_netmodels()
+        for pref in prefs:
+            if pref in supported_models:
+                return pref
+        return None
 
-        if net_model:
-            for net in self.devices.interface:
-                if not net.model:
-                    net.model = net_model
+    def _set_net_defaults(self):
+        default_model = self._default_netmodel()
+        for net in self.devices.interface:
+            if not net.model:
+                net.model = default_model
 
     def _set_sound_defaults(self):
         if self.os.is_q35():

virtinst/osdict.py

@@ -340,14 +340,8 @@ class _OsVariant(object):
         return self._is_related_to(
                 ["debian8", "fedora18", "rhel6.0", "sles11sp4"])
 
-    def default_netmodel(self):
-        """
-        Default non-virtio net-model, since we check for that separately
-        """
-        for devname in self._device_filter(cls="net"):
-            if devname in ["pcnet", "ne2k_pci", "rtl8139", "e1000"]:
-                return devname
-        return None
+    def supported_netmodels(self):
+        return self._device_filter(cls="net")
 
     def supports_usbtablet(self):
         return bool(self._device_filter(cls="input", name="tablet", bus="usb"))