refactor: Break up RbacMalformedException into discrete exceptions

This patch set breaks up RbacMalformedException into the following
discrete exceptions:

* RbacMissingAttributeResponseBody
* RbacPartialResponseBody
* RbacEmptyResponseBody

Each of the exception classes deals with a different type of
failure related to a soft authorization failure [0] which
means that a failure occurred server side related to RBAC
authorization, but the result of which an incomplete, partial
or empty response body (with a 2xx status code).

* incomplete means that the response body (for show or list)
  is missing certain attributes
* partial means that a list response only returned a subset of
  the possible results available.
* empty means that the show or list response body is entirely
  empty

Because RbacMalformedException is not part of a stable library
it is removed altogether; we do not need to deprecate it.

[0] http://git.openstack.org/cgit/openstack/patrole/tree/doc/source/rbac-overview.rst#n232

Story: 2003843
Task: 26633
Change-Id: I2c76c3c4d226e4877fc9d1e93707edfc230a1be4
diff --git a/releasenotes/notes/break-up-rbac-malformed-exception-into-discrete-exceptions-92aedb99d0a13f58.yaml b/releasenotes/notes/break-up-rbac-malformed-exception-into-discrete-exceptions-92aedb99d0a13f58.yaml
new file mode 100644
index 0000000..0a93b64
--- /dev/null
+++ b/releasenotes/notes/break-up-rbac-malformed-exception-into-discrete-exceptions-92aedb99d0a13f58.yaml
@@ -0,0 +1,25 @@
+---
+features:
+  - |
+    The exception class ``RbacMalformedException`` has been broken up into the
+    following discrete exceptions:
+
+    * ``RbacMissingAttributeResponseBody`` - incomplete means that the
+      response body (for show or list) is missing certain attributes
+    * ``RbacPartialResponseBody`` - partial means that a list response
+      only returned a subset of the possible results available.
+    * ``RbacEmptyResponseBody`` - empty means that the show or list
+      response body is entirely empty
+
+    Each of the exception classes above deals with a different type of failure
+    related to a soft authorization failure. This means that, rather than a
+    403 error code getting returned by the server, the response body is
+    incomplete in some way.
+upgrade:
+  - |
+    The exception class ``RbacMalformedException`` has been removed. Use one
+    of the following exception classes instead:
+
+    * ``RbacMissingAttributeResponseBody``
+    * ``RbacPartialResponseBody``
+    * ``RbacEmptyResponseBody``