Fix KeyError for type

Not all fields are always present. When changing an attribute type is not present in the form because it can only be setup during Attribute creation.

Author: kofrezo

serveradmin/serverdb/forms.py

@@ -41,10 +41,12 @@ class Meta:
         fields = '__all__'
 
     def clean(self):
-        if self.cleaned_data['type'] != 'relation' and self.cleaned_data['target_servertype'] is not None:
+        attr_type = self.cleaned_data.get('type') or self.instance.type # New or existing attribute ?
+
+        if attr_type != 'relation' and self.cleaned_data.get('target_servertype') is not None:
             raise ValidationError('Attribute type must be relation when target servertype is selected!')
 
-        if self.cleaned_data['type'] == 'inet' and self.cleaned_data['multi'] is True:
+        if attr_type == 'inet' and self.cleaned_data.get('multi') is True:
             raise ValidationError('Multi attributes of type inet are not supported!')
 
         super().clean()