blueprint cisco-plugin-exception-handling

blueprint cisco-plugin-exception-handling

Improvements to exception handling in the Cisco plugins. Changes
include:

- Added mapping of Cisco exceptions to HTTP codes
  (extension to FAULT_MAP).
- Removed several unused Cisco exception definitions.
- Added several new Cisco exceptions for fault conditions.
- Added several rollbacks for various sequential operations, e.g.:
  * Create port: Nexus sub-plugin fails after OVS sub-plugin success
  * Create port: Nexus switch conig fails after adding binding to
                 Nexus binding database
  * Delete port: OVS sub-plugin fails after Nexus sub-plugin success
- Delete Port: Reversed order of OVS/Nexus sub-plugin calls so that
  it is done in the reverse order as is done for create port.
- Removed several empty except/raise blocks
- Delete network: Removed call to Nexus sub-plugin delete_network,
  since that is a no-op.
- Removed a block of unused code in model's create_network method.
- Added several unit testcases, including patching of OVS, Cisco
  and Nexus config.
- Remove CISCO_TEST configuration from cisco plugin
  config .ini file.

Change-Id: Iabdf4842aa2f0b090a90e2c565848290832b5197