Fix deleting repos when sec scan or signing is disabled

Make sure we don't invoke the APIs to non-existent endpoints

util/abchelpers.py

@@ -0,0 +1,20 @@
+class NoopIsANoopException(TypeError):
+  """ Raised if the nooper decorator is unnecessary on a class. """
+  pass
+
+
+def nooper(cls):
+  """ Decorates a class that derives from an ABCMeta, filling in any unimplemented methods with
+      no-ops.
+  """
+  def empty_func(self_or_cls, *args, **kwargs):
+    pass
+
+  empty_methods = {}
+  for method in cls.__abstractmethods__:
+    empty_methods[method] = empty_func
+
+  if not empty_methods:
+    raise NoopIsANoopException('nooper implemented no abstract methods on %s' % cls)
+
+  return type(cls.__name__, (cls,), empty_methods)