Revise custom exceptions to require a message

Reduce code redundancy in controller exception handling.
Raise exception on ID mismatch in create policy type request.
Add test of ID mismatch case.

Signed-off-by: Lott, Christopher (cl778h) <cl778h@att.com>
Change-Id: I2c020f41d65b7ddadd71185fafb16cf2c4557a88
diff --git a/docs/release-notes.rst b/docs/release-notes.rst
index 8febae6..791e912 100644
--- a/docs/release-notes.rst
+++ b/docs/release-notes.rst
@@ -14,16 +14,17 @@
    :depth: 3
    :local:
 
-[2.1.8] - 2020-04-29
+[2.1.8] - 2020-04-30
 --------------------
 
 * Revise Dockerfile to set user as owner of .local dir with a1 package
-* Rename console shell start script to run-a1 from run.py 
+* Rename console shell start script to run-a1 from run.py
 * Extend start script to report webserver listening port
 * Add tiny RMR routing table for use in demo and test
 * Extend documentation for running a container locally
 * Add documentation of start/init parameters to _RmrLoop class
 * Add new environment variable USE_FAKE_SDL (`RIC-351 <https://jira.o-ran-sc.org/browse/RIC-351>`_)
+* Respond with error if policy type ID differs from ID in object on create
 
 
 [2.1.7] - 2020-04-28