models.py: minor branch tweaks

Make minor (non-structural) improvements to the model, mostly for the
benefit of the admin interface:

* Set default ordering so that branches appear in the same order they do
  in the user-facing drop-down
* Include the description in the default string representation (so you
  know which branch name matches with which Yocto Project version, in
  the OE index).

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>

layerindex/models.py

@@ -42,9 +42,13 @@ class Branch(models.Model):
 
     class Meta:
         verbose_name_plural = "Branches"
+        ordering = ['sort_priority']
 
     def __str__(self):
-        return self.name
+        if self.short_description:
+            return '%s (%s)' % (self.name, self.short_description)
+        else:
+            return self.name
 
 
 class Update(models.Model):