Use .qcow2 extension when creating qcow2 files

Seems the be the practice these days

virtManager/addstorage.py

@@ -67,8 +67,9 @@ class vmmAddStorage(vmmGObjectUI):
 
     def _get_ideal_path_info(self, name):
         path = self._get_default_dir()
-        suffix = ".img"
-        return (path, name, suffix)
+        fmt = self.conn.get_default_storage_format()
+        suffix = virtinst.StorageVolume.get_file_extension_for_format(fmt)
+        return (path, name, suffix or ".img")
 
     def _get_ideal_path(self, name):
         target, name, suffix = self._get_ideal_path_info(name)

virtManager/createvol.py

@@ -113,10 +113,10 @@ class vmmCreateVolume(vmmGObjectUI):
         return ret
 
     def default_suffix(self):
-        suffix = ""
-        if self.vol.file_type == self.vol.TYPE_FILE:
-            suffix = ".img"
-        return suffix
+        if self.vol.file_type != self.vol.TYPE_FILE:
+            return ""
+        return StorageVolume.get_file_extension_for_format(
+            self.get_config_format())
 
     def _init_state(self):
         blue = Gdk.color_parse("#0072A8")
@@ -255,6 +255,7 @@ class vmmCreateVolume(vmmGObjectUI):
         ignore = src
         self._show_alloc()
         self._show_backing()
+        self.widget("vol-name").emit("changed")
 
     def browse_backing(self, src):
         ignore = src

virtinst/cli.py

@@ -1453,8 +1453,9 @@ def _parse_disk_source(guest, path, pool, vol, size, fmt, sparse):
                 disk.get_vol_install().pool.name() == poolobj.name()):
                 collidelist.append(os.path.basename(disk.path))
 
+        ext = virtinst.StorageVolume.get_file_extension_for_format(fmt)
         vname = virtinst.StorageVolume.find_free_name(
-            poolobj, guest.name, suffix=".img", collidelist=collidelist)
+            poolobj, guest.name, suffix=ext, collidelist=collidelist)
 
         volinst = virtinst.VirtualDisk.build_vol_install(
                 guest.conn, vname, poolobj, size, sparse)

virtinst/storage.py

@@ -463,6 +463,14 @@ class StorageVolume(_StorageObject):
     ALL_FORMATS = ["raw", "bochs", "cloop", "cow", "dmg", "iso", "qcow",
                    "qcow2", "qed", "vmdk", "vpc", "fat", "vhd", "vdi"]
 
+    @staticmethod
+    def get_file_extension_for_format(fmt):
+        if not fmt:
+            return ""
+        if fmt == "raw":
+            return ".img"
+        return "." + fmt
+
     @staticmethod
     def find_free_name(pool_object, basename, **kwargs):
         """