Sync Qpid RPC fix from Oslo

Qpid cannot serialize dicts containing strings longer than 65535
characters.  This change syncs the fix from Oslo to Quantum.

Fixes bug 1175808

Change-Id: I48071abffa86e71727deed05aca08ac475cbaf05
Remove generic Exception when using assertRaises

This change fixes errors associated with H202 checks and enables H202
checks.

Change-Id: I28a48d1b58f2f1f6824ee4b45782a0c961fe9fb5
Merge "Remove generic Exception when using assertRaises"
Merge "Sync Qpid RPC fix from Oslo"